Heat the olive oil in a large nonstick skillet over medium heat.
Add the whisked egg and green onion. Cook, stirring often until the eggs are set, about 3 minutes. Transfer to a bowl.
Place the tortilla in the skillet, and over one half of the tortilla, sprinkle with the eggs, black beans, and shredded cheese. Fold the tortilla over the toppings, and let cook for 2 to 3 minutes per side, until the cheese has melted.