Heat 1 tbsp oil in a pan. Put the onion in the pan and cook over a medium heat for 1-2 minutes or until translucent. Take out of pan and set aside. Put another 1 tbsp oil in the pan, add the peppers, and cook for around 5-7 minutes or until softened. Take the peppers out of the pan as well.
Put the beans in a bowl and crush using a fork. Add the cooked onion and peppers, as well as chopped parsley, eggs, and bread crumbs. Mix until well combined. Season with salt and pepper, and add chili powder (the last one optional).
Make patties by hand and fry them in the oiled pan over a medium heat for about 2 minutes on each side or until uniformly golden brown, adding more oil if needed. Serve the patties hot, as per your tastes, preferences, and dietary requirements.