Preparation - Brown the ground beef in skillet; drain. Stir in the taco seasoning and water and simmer for about 5 minutes. Remove from heat, stir in the beans, and set aside. In a blender or food processor, blend the canned tomatoes, tomato paste, chopped onion, minced garlic, and salt together. Place 3 tortillas in the bottom of a crockpot. Layer about one third of the beef and bean mixture, one third of the tomato sauce and one third of the cheddar cheese on top. Repeat each layer two more times, ending with the cheddar cheese. Cover and cook on low for 6 to 8 hours.