Tucson’s finest street taco, Mexico City–style, used to be found in a food truck called Seís, Spanish for “six,” after the six Mexican food regions from which the menu drew. Then the owners found a location in Tucson’s ultrahip Mercado San Agustín, the anchor of a booming west-of-the-freeway downtown scene. From opening to closing, you’ll find a long line at the order window, but plenty of seats in the spacious, leafy plaza. Try the fiery chicken tinga or the pork al pastor, to name just a couple of possibilities. Top it off with an order of calabacitas, or stewed squash. A second location in the Joesler Village shopping center across from St. Philip’s Plaza (1765 E. River Rd. #131; tel. 520/612-7630) is just as good as the mothership. The food truck is still in service for catering, too.