Seed and chop the green bell pepper.
Open and drain the black beans.
In a large skillet, brown the ground beef with the taco seasoning and chopped bell pepper. Drain and return to the skillet, then stir in the black beans and let simmer for 5 to 7 minutes. Then, remove from the heat.
Chop the tomato.
In large mixing bowl, toss together the lettuce leaves, chopped tomato, shredded cheese, Doritos chips and beef and bean mixture. Gently toss in the salad dressing.
Serve Doritos Taco Salad.