1. In a large mixing bowl, combine the cooked quinoa, black beans, beaten egg, bread crumbs, chopped onion, garlic powder, cumin, salt, and black pepper.
2. Mix well until all ingredients are evenly combined.
3. Form the mixture into 4 equal-sized patties.
4. Heat olive oil in a frying pan over medium heat.
5. Cook the patties for about 5-7 minutes on each side, or until golden brown and cooked through.
6. Serve the quinoa burgers on buns with your favorite toppings.