My not-very-brave friend looked at the premade tacos drying out under the warmer in the front window and asked "Am I going to get sick from this place?" We headed in and were peered at by the Latino men eating at all the tables. But Sandy the proprietress greeted us warmly and led us to a roomy spot, where we ordered trenchermen's portions for $27.
For nibbles we had a taco de pavo (turkey) and chicken salbutes, each $1.50. The salbutes are the way to go, nice thick tortilla all chewy under some of that tasty roast chicken they're becoming known for, sliced avocado, pickled onions and black pepper. I loved the super-hot salsa.
I was underwhelmed by the banh mi, though the chicken was great. The sandwich was dry and haphazardly garnished. But we got two winner entrees, the entomotado de puerco and the pescado empanizado. The former was a bowl of really rich, soft to the point of being almost creamy, gamy pork (I think there was a piece of foot in there) swimming in thick tomato sauce, with a pile of small tortillas and another bowl with a thin black bean puree. You fill one after another of those tortillas with the saucy pork, dip it into the black beans as you go along, and wow. The breaded fish was bits of a flat fillet, clean-tasting, not greasy, plated with more pickled onion and avocado, white rice sprinkled with black pepper, and another bowl of black bean puree. More delicious roll-your-own tacos. We must have had eighteen of those little tortillas. Sandy couldn't believe we ate it all (I take most of the credit).
We got more backstory from Sandy's husband David (nice Vietnamese name). He was an electrical engineer in Silicon Valley until his company went belly-up three years ago. One of his brothers invited the couple to run his bodega a few doors down Mission Street while he pursued some other business. They poured all their energy into the store, spent day and night there and really built up the business. They noticed that nearly all their business came from these single guys who had just moved here from the Yucatan, who came in after work to get this and that to eat for their dinner as they had no domestic life whatsoever. They became pals with the guys, and when the brother ultimately returned to reap the fruits of their labor (he hinted at high drama and family feuds), they decided to stay in the neighborhood and find some cooks to make lunch and dinner for these locals. And they've been so surprised and delighted lately to see these gringas wander in, seemingly all of whom have heard of them through Chowhound.
What a happy place. Thanks for the discovery, OP! With Thrift Town on the corner, that block of Mission Street is officially Heaven!