In a large non-stick pan sauté beef over medium heat, breaking up with a spatula, until no longer pink – about 10 minutes. Drain off fat in a colander with running water and return to the pan.
Add onions to the pan with the ground beef and sauté until onions are translucent about 5 minutes.
Add garlic, peppers, cumin, chili powder, oregano, red pepper flakes if using, salt and pepper and cook over medium heat for another 5 minutes.
Add black beans, tomatoes with juice and tomato paste and bring to a boil.
Reduce heat and simmer uncovered, stirring occasionally until slightly thickened, about 20 minutes.
Stir in corn and heat through.
Spread into a 9 x 13 inch baking pan. You can spread 3/4 in the pan and keep 1/4 aside in a container for a taco salad the next day. Meat mixture should be refrigerated until ready to serve. For take home you will need chips, cheese and green onions.
Just before dinner sprinkle with enough chips to cover the meat mixture. Then sprinkle with grated cheese.
Bake at 375 degrees for 15-25 minutes until mixture is hot and cheese is melted.
Serve with a spatula onto plates. Sprinkle with green onions and add toppings if desired.
Shredded lettuce, sour cream, salsa and guacamole.