Preheat the oven to 350°F then spray at 9×13" baking-pan with cooking spray.
In a large-skillet cook the beef, onion & pepper over medium-heat till the meat is no-longer-pink. Drain off any fat.
Add taco seasoning packets and water. Bring to a boil, then educe heat and simmer, uncovered for 2minutes.
Stir in tomatoes (with juice) and black beans. Simmer, uncovered for 10minutes.
Place 2-tortillas in the bottom of a greased 13×9" baking-dish. Break a third tortilla and piece it together in any holes to create as much of a whole layer of tortillas.
Spread with half the refried-beans and half the beef mixture, then sprinkle with 1 cup cheese.
Spread with half the refried-beans and half the beef mixture, then sprinkle with 1 cup cheese. Repeat layers (3 tortillas, remaining beef, remaining beans, 1 cup of cheese).
Top with remaining tortillas and 2-cups cheese. Cover with foil and bake at 350°F for 25-30 minutes or till heated through and cheese is melted.
Serve with fresh pico de gallo and sour cream.