Add onion, garlic, green pepper, tomatoes, tomato sauce and spices to skillet. Cook for 5-10 minutes, until vegetables are tender. Turn heat on low to keep warm.
Beat 3 eggs, add salt and pepper, and pour egg mixture into skillet. Cook eggs until firm on bottom, and flip. Remove from heat.
Add stuffed pepper mixture to half the omelet. Top with shredded cheese, and fold over.