1. Spray a nonstick skillet over medium-high heat.
2. Add spinach and cook, stirring, until wilted, 2 minutes.
3. Whisk together eggs and egg whites in a small bowl. Add eggs to skillet and cook, stirring, until cooked through, 3–4 minutes. Season with salt and pepper.
4. Place 1/4 of egg mixture in the center of each tortilla, and sprinkle with 1 ounce cheese.
5. Top with 4 slices avocado and fold, burrito-style. Slice in half and serve.