In a large bowl, mash the black beans with a fork until they form a paste.
Add in the cooked quinoa, rolled oats, diced onion, garlic, cumin, chili powder, smoked paprika, salt, and pepper. Mix until well combined.
Divide the mixture into 4 equal portions and form each into a patty.
Heat the olive oil in a large skillet over medium-high heat. Add the patties and cook for 4-5 minutes on each side or until golden brown and crispy.
While the patties are cooking, prepare the burger toppings by toasting the buns and slicing the tomato, onion, and avocado.
To assemble the burgers, place a lettuce leaf on the bottom bun, followed by the veggie patty, sliced tomato, onion, and avocado. Add ketchup or mustard if desired, then top with the other half of the bun.
Serve immediately and enjoy!
