I just read an interesting article on sandwiches in the NYTimes that described a Cemita Poblano:
"A cemita has the familiar look of a Big Mac — until you bite into it. To absorb the layers of spicy meat, soft avocado, fluffy bread and the thick flesh of whole chili peppers is to leave the fast-food nation forever."
I must have this sandwich! Does anyone know if one can be found the Bay Area? Apparently it's a specialty of the Mexican state of Puebla.