In a large bowl, mash black beans with a fork until mostly smooth. Add cooked quinoa, chopped onion, cilantro, minced garlic, chili powder, cumin, salt, and pepper. Mix well to combine.
Form the mixture into 4 equal-sized patties.
Heat a skillet over medium heat. Cook the patties for about 5-7 minutes per side, or until golden brown and heated through.
Serve the quinoa and black bean burgers on whole wheat buns with your favorite toppings.
Notes
For a spicier burger, add a pinch of cayenne pepper to the mixture.