Bake corn tortillas on oven rack or cookie sheet until golden & toasted on 375°. Leave the oven on. Spread black or pinto refried beans on tortillas then sprinkle cheese and add shredded chicken or cooked ground beef, if desired. Cook until cheese is melted. Remove and turn off oven. Serve with shredded lettuce, olives, chopped tomatoes, jalapenos, sour cream, green chili, etc.