Cook the ground beef along with the chopped onion and green pepper in a large skillet, over medium-high heat, until no pink is left on the meat
Add water and taco seasoning. Simmer for a couple of minutes
Mix in the drained black beans and the undrained Mexican tomatoes. Simmer for 10 minutes
Preheat the oven to 350F. Grease a 9 x 13-inch baking dish and place two tortillas on the bottom.
Spread half of the refried beans on top of the tortillas.
Spoon half of the meat mixture over the refried beans.
Sprinkle 1 cup of cheese over the meat mixture.
Repeat the layers ending with a layer of tortillas and the last cup of cheese. Bake for 25-30 minutes or until the cheese is melted and bubbly. Top with your favorite toppings, and serve.