Place pepper and onion in food processor and blend until finely chopped (if there's a lot of water after blender, strain it out using a mesh strainer). If you don't have a food processor, grate or finely chop peppers and onions.
Mash black beans in large bowl. Add peppers/onions, egg, breadcrumbs, chili powder, cumin and garlic powder. Season with salt and pepper, to taste, and mix well. Divide into 4 patties.
Heat oil in skillet over medium heat. Add patties and cook 6-8 minutes on each side.