This unassuming storefront in Arlington is unlikely to get an award for its hospitality or win a prize for its design, and that’s just fine with owner Sunthorn Rojural. “We want to win customers with our food,” says the Bangkok native. I love his priorities. Even more, I treasure Thai Square’s epic menu, where even familiar dishes taste brighter, fresher, zestier than just about any competitor’s. Take the restaurant’s fish cakes, made in small batches from imported feather fish, mashed by hand with curry paste and lime zest and fried to a delicate crisp. Or duck marinated in honey, roasted, and fried to order with chilies and Thai basil, a glossy entree whose fragrant aroma precedes its arrival. Who knew that Chinese eggplant stir-fried with tofu could bring conversation to a halt? Every visit to the 18-year-old standard-bearer finds a new favorite. Right now, No. 12, nam sod, has my heart. Your lips will burn, you might break into a sweat, but chances are good, thanks to such fireworks as fresh ginger and lime juice, that you won’t leave a trace of the minced pork salad behind. Nam sod is a signature contribution of opening chef Nongyao Augustin and a salute to Northeast Thailand, where she’s from. While the senior citizen no longer cooks every day, she shows up for regular quality checks. Count me a huge fan — along with regulars Johnny Monis and his wife, the owners of that other Thai treasure, Little Serow, in the city.