Put the oats in the small bowl of a food processor and process until coarsely ground—it shouldn't be flour-like, but there should be very few whole oats left when you're finished.
Place the black beans in a medium bowl. Use a fork to partially mash them, then fold in the oats, corn, green onions, garlic, and salsa. Sprinkle the cumin, chili powder, oregano, paprika, and cayenne over the top of the mixture and then stir them in too. Add salt and pepper to taste, then mix in the beaten egg.
Spray a mini-muffin tin with oil. Form the black bean mixture into 12 balls and place each in a muffin cup. Bake for 20-30 minutes, or until the tops of the meatballs are dry to the touch and just beginning to brown. Let the meatballs cool for about 5 minutes, then carefully run a butter knife along the edges of the muffin cups to loosen them and pop them out of the muffin tin. Serve with salsa or in wraps, burritos, as meatball sliders or subs, etc.
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