Tlacoyos are Mexican cornmeal dough pockets similar to Salvadorian pupusas. (Doesn't every culture in the world have some kind of edible pocket stuffed with filling? Calzones? Pork buns?) Working with masa is quick, and so is the filling: a can of beans mashed up with sauteed onion and garlic, and Oaxaca cheese, which is basically a Mexican version of string cheese.