Heat olive oil in a large skillet over medium heat. Add the spinach and sauté until wilted. Add the black beans and cooked quinoa, stirring to combine. Season with salt and pepper.

In a separate bowl, whisk the eggs with a pinch of salt and pepper. Pour the eggs into the skillet with the quinoa mixture and cook, stirring occasionally, until the eggs are scrambled and fully cooked.

Lay the tortillas flat and evenly distribute the egg mixture onto each one. Top with salsa, avocado slices, and cheese.

Roll each tortilla into a burrito, tucking in the ends to secure. Serve warm.