It's no coincidence that, a few short months after Westport Plaza's Drunken Fish sushi lounge opened a second St. Louis location in the Central West End, burgeoning fast food (sorry, fast-casual) chain SanSai Japanese Grill will likewise expand to its next area outpost in downtown Clayton (which should be happening right around...now). Sushi has so permeated the American culinary landscape, it now ranks as both sexy finger food and workingman's lunch. SanSai, a counter-service chain that got its start in Southern California before heading here, looks poised to corner the market on the latter, and deservedly so. The menu is simple, healthy, reasonably priced and tasty: tempura, teriyaki, soups, salads and, yes, sushi. Less than ten bucks, for example, buys you a delicious sashimi tuna salad -- slices of blushing raw fish, proffered on baby greens and frisée -- with sides of miso soup and rice. What you don't get is that complimentary side of guilt that comes with most other fast-food meals.