Rinse 1/2 cup of dry quinoa under cold water to remove any bitterness. In a small pot, combine the rinsed quinoa with 1 cup of water. Bring to a boil, then reduce to a simmer, cover, and cook for about 15 minutes or until all the water is absorbed. Fluff with a fork and set aside to cool.
In a large mixing bowl, add the drained black beans. Using a fork or a potato masher, mash the beans until they are mostly smooth, leaving some chunks for texture.
To the mashed black beans, add the diced onion, cooked quinoa, diced green chilis (with juice), panko breadcrumbs (or crushed nuts), black pepper, sea salt, cumin, chili powder, oregano, and red pepper flakes (if using). Mix everything together until well combined.
Preheat your oven to 375°F (190°C). Using your hands, form the mixture into small balls, about 1 to 1.5 inches in diameter. Place the formed meatballs on a greased sheet pan, ensuring they are spaced evenly apart.
Lightly spray the tops of the meatballs with olive oil or non-stick cooking spray. Bake in the preheated oven for 25-30 minutes, or until they are golden brown and firm to the touch.
Once baked, remove the meatballs from the oven and let them cool slightly. Serve with your favorite dipping sauce, over a bed of rice, or in a taco with fresh toppings like avocado, salsa, and cilantro. Enjoy your delicious Southwestern (Meatless) Meatballs!