Sandia appeared in the Flatiron district back in January like a hothouse fruit; now, with warm weather, it has begun to ripen. The vibrant Latin-Asian cuisine, sunny decor, and refreshing tropical drinks, slightly dissonant in winter, suit the warmer seasons handsomely. Sandia means “watermelon” in Spanish, and the restaurant’s melon references are overt: juicy pink walls bounded by green columns; big flower photos with banana-colored accents. Jerri Banks, who has created cocktails around the city, designed a watermelon-heavy cocktail list, as well as an excellent, wide-ranging wine list that categorizes wines by their fruit character.

Chef Roberto Pagan’s menu fuses Asian flavors and techniques onto a sturdy Nuevo Latino foundation. The marriage is a smooth one. Both parent cuisines have compatible ways of highlighting savory flavors with jolts of sweetness or tartness, and emphasize subtly complex spicing. To start, Mr. Pagan, who cooked at Chicama, offers an assortment of inventive sushi rolls. One ($10) containing rare five-spice-scented beef and crunchy long beans is wrapped in rice and then in supple strips of cooked mushroom: the combination is earthy, strange, and enjoyable. Crisp-cooked salmon skin fills a rich, salty, somewhat familiar roll ($9), but the luxurious addition of bacon and creamy queso fresco gives it a new twist, and a delicious but easily overlooked squirt of mayonnaise on the plate has the bright scent of calamansi, a vivid-flavored tropical relative of the tangerine.

Mr. Pagan proves himself proficient with a variety of tropical produce. He serves taquitos ($6) in brittle shells made from malanga, a starchy taro-like root. The little tacos are filled with a choice of tomatoey Cuban-style shredded beef or mesquite-tangy smoked fish puree. Creamy-textured scallops ($8), served with a smoky roasted-pineapple salsa, have a crisp fried coating made from earthy yuca root. A pair of ceviches ($12) shine as well: one a brash and red shrimp cocktail with plenty of garlic and heat, the other dry, pale green with herbs, and consisting of chunks of scallops, crunchy jicama, and pineapple. An almost-entree-size calamari salad ($8) contains spicy glazed nuts, miniature banana slices, jicama, and lightly bitter greens – the calamari itself, batter-fried and lacking salt, is the least exciting element of the complexly balanced mixture.

Main courses are no less dramatic: notably a delicious whole red snapper ($21), which is shaped into a sort of hollow vessel. The deft chef debones the fish, batter-fries it to a crisp firmness so it holds its bowl-like shape, and stuffs the interior with fried chunks of yuca, pineapple, and whole shrimp. The crunchy, moist-fleshed snapper is served upright, in swimming position, with a pesto sauce, chili glaze, and bed of baby greens; the succulent, complementary morsels within can be eaten out of the fish first, as a built-in appetizer, or the fish can be eaten around them and with them in alternating bites.

A grilled sirloin steak ($24) comes thickly pre-sliced, with each flavorful slice resting on its own thick fried yuca strip. Szechuan pepper gives the meat’s seared crust a unique tangy tingle, and the garlicky, dense yuca makes an admirable starch complement. But a “wok-charred” skin-on salmon filet ($20) shows no sign of char, and little under its soy glaze to distinguish it from a million other salmon filets. A bed of pineapple fried rice, like the fish, is serviceable but not special. Pieces of white-meat chicken ($18) with fivespice seasoning rises to the occasion with intense, delicate flavor, but suffers from the cottony texture that plagues so many chicken breasts, and a generic-tasting sweet plum sauce lends it the banal flavor of takeout Chinese. A similarly Chinese accompaniment of scallion- and cucumber-filled wraps gives textural contrast.

Hot little cinnamon-dusted churro nuggets ($6) make an exceptional dessert, light and sweet and just rich enough. Two dipping sauces – chocolate and dulce de leche – are available for lily-gilders. The other desserts, like coconut lychee flan ($6) and almond cookies ($4), run a distant second to the churros.

Cocktails make up a central part of the Sandia experience. The Yellow Doll ($12) is a particular beauty, mild, refreshing, and complex, made with juice from the sweet Yellow Doll watermelon, tinged with elderflower and fortified with vodka. The watermelon theme continues in the Slice of Paradise ($13), a frozen margarita with lush watermelon and honeydew juice and the cultured bite of El Jimador tequila. Other highlights include the Blushing Roseberry ($13) a quintessentially Banksian frozen concoction of lime juice and Hendrick’s sui generis gin, swirled with rose-petal syrup; and the Easter Island Punch ($12), made with pisco and calamansi and pomegranate juices. The wine selection has just as much variety and verve, with 40 or so bottles touching on two dozen varietals and helpfully organized under six fruity rubrics, such as “apple, green grape, citrus” and “blackberry, cassis, plum.” That first group in particular offers some excellent foils to Sandia’s food, including a crisp and simple gruner veltliner from Wachau ($9/glass), and Wishing Tree’s tangy chardonnay ($8/glass), whose exemption from the pervasive oak-barrel aging makes it an entirely different chardonnay. Red choices are no less inspired: a supple, ripe Mendozan bonarda that’s a bargain at $7 a glass, and Cristom Vineyards’ Mount Jefferson pinot, a silky one that thrives in the company of grilled meat.

A few managerial bungles, like incorrect prices on the menu, detract slightly from the experience, but the service is gracious and inviting. The colorful, well-designed environment feels comfortable and much more spacious than it really is: between that, the drinks, and the food, the illusion of a balmy paradise is readily invoked. At this rate, next winter at Sandia should be a tropical delight.

Sandia, 111 W. 17th St., 212-627-3700.