Please, please let this be a place that sells Tijuana-style, real taco-stand Mexican street food. With shredded beef tacos and burritos on the menu, with the latter not stuffed with rice and beans unless you specify that.
A place with a little condiment bar with sliced radishes, lemon wedges, various hot sauces, not just habanero sauce in a bottle, and salsa. A place with authentic Mexican old-style music playing.
Pretty please with dulce on top?