Heat the oil in a skillet or frying pan over medium heat.
Add the onion, pepper, and garlic, if using, then sauté stirring occasionally for 2-3 minutes.
Add the tomatoes, tomato paste, paprika, salt, and pepper. Cook for about 10 minutes on medium to high heat, stirring occasionally.
Drain and rinse the beans and add to the pan. Cook for 2 minutes.
Serve with some warm tortillas on the side or with rice, if you prefer.