Preheat over to 375 degrees.
In a skillet, over medium heat, add the beef, refried beans and tomato sauce. Cook just till warm and mixed together.
Fill each taco shell or tortilla with stuffing. Put them in a casserole dish standing up. I left mine flat on a baking sheet because I used flat tortilla shells.
Sprinkle cheese on top and put in the oven for 10 minutes or until cheese melts.
Top with onion, cilantro, salsa or whatever you wish. Enjoy!!
*An alternative to using the crockpot beef would be browning ground beef, drain completely when done, and add taco seasoning.