The term "practical perfectionist" might seem an oxymoron, but for Jason Smith, it's a way of life.

Smith's first restaurant, 18 Seaboard, was a hit the day it opened in 2006, but that hasn't stopped the young chef from fine-tuning the restaurant. His seasonally evolving American bistro menu deftly walks a culinary tightrope between his passion for local produce (for which Smith credits his mentor, Magnolia Grill chef Ben Barker) and his desire to keep prices low.

With the March opening of Cantina 18 in Cameron Village, Smith takes his high-wire act in a new direction, which he calls "Southwestern-inspired cuisine." The emphasis, he points out, is on "inspired," as reflected in a menu that freely wanders from blackened shrimp quesadilla to adobo-grilled chicken taco with apples, cranberries and goat cheese.

It's a risky undertaking, to be sure, and the kitchen's performance has indeed been wobbly in the early going. Fortunately, the talents and perfectionism of the restaurant's owner provide a reliable safety net. Smith has already taken the menu through three revisions, tweaking dishes that are near-misses and eliminating the outright failures.

In the most recent revision, a Veracruz-style mahi mahi stew whose star ingredient got lost in a dense, dry mélange of red rice, olives, capers and onions, was mercifully sent to the sidelines. Another entree offering of crispy pork shank morphed into carnitas that more consistently live up to their "crispy" billing. More greenery was added to entree salads such as the grilled steak and chorizo with blackened blue cheese dressing and avocado, an otherwise winning combination that was at times inexplicably stingy with its least expensive ingredient. The duck confit taco with pineapple salsa gave way to a more seasonally appropriate filling of seared tuna and cucumber-jicama slaw.

Tacos, which are made with soft flour tortillas and generously filled, are deservedly popular. A filling of lime-marinated seasonal vegetables with tomatillo salsa and chihuahua cheese is a welcome vegetarian option. Cornmeal-crusted mahi mahi is a good bet, too, if you don't mind the fact that the crust gets softened a bit by the zesty tomatillo-arbol chile salsa. I'm partial to the spicy beef brisket and the pork carnitas (a variation on the entree offering, topped with avocado crema and pickled poblanos), both recent additions to the menu.

Not typical Tex-Mex

If the tacos don't sound like anything you'd get from an authentic taqueria, neither will the nachos strike you as typical Tex-Mex fare. Options include pineapple-barbecue chicken, cilantro shrimp (from North Carolina waters, naturally) and a colorful patchwork of pickled corn, roasted poblanos, black beans, crumbled goat cheese and juicy shreds of beef short rib. All are eminently shareable starters, the only problem being agreeing on which combination you want to nibble with your peach mango sangrias or pints of draft Dos Equis. Unless, that is, you opt for the runaway hit Skinny Girl margaritas that you'll see on many of the tables in Cantina's rustically contemporary dining room and on its umbrella-shaded sidewalk patio.

On the other hand, you probably won't want to share your bowl of tropical gazpacho, a refreshing twist on the classic chilled tomato soup punctuated with pineapple, cilantro and mint. Chipotle grilled shrimp are a worthy starter, too, provided you have a sweet tooth. The shrimp are glazed with an adobo-honey barbecue sauce that's decidedly more sweet than spicy, and the accompanying fried plantains are lightly dusted with sugar.

Adobo grilled salmon with wilted spinach and a warm tomato and corn relish, which took the seafood spot vacated by the mahi stew on the entree list, is a definite keeper. So is grilled skirt steak with black bean succotash and a vibrant chimichurri sauce, another recent addition to the menu.

I've been to Cantina 18 three times, and each visit has been a marked improvement over the preceding one. The last time, the only disappointment was a grainy, overcooked Escazu chocolate flan. Knowing the restaurant's practical perfectionist owner, I wouldn't be surprised if that's fixed by the time you get there.