Heat the oil in a large nonstick skillet over medium heat. Add the onions and peppers to the skillet and season them with salt and pepper. Cook, stirring occasionally, until softened, 7-8 minutes. Stir in the beans and chili powder and cook another 2-3 minutes until heated through. Pour the contents of the skillet into a bowl and set aside. Wipe the skillet clean.
Whisk the eggs and egg whites together in a large bowl along with ½ teaspoon salt and ¼ teaspoon black pepper. Spray the skillet with nonstick cooking spray and heat over medium heat. Add the eggs and cook them, stirring occasionally, until soft curds form. Stir in the cheese and cook another minute until melted. Remove from heat.
Spread each tortilla with equal amounts of the veggie/bean mixture and top with the scrambled eggs. Spread 2 tablespoons salsa, some sliced scallions and hot sauce (if using) on top. Roll the tortillas up burrito style- fold the side closest to you over the filling, then fold both sides in toward the center and roll up. Serve alone or with reduced fat sour cream, if desired.
If not eating right away, wrap each burrito in plastic wrap or aluminum foil and freeze. To reheat, unwrap and microwave until warm, about 2 minutes, turning over halfway through. For a crispier wrapping, heat in the microwave, then bake in a 450° oven for 5 to 10 minutes.