Combine first 5 ingredients in a bowl, stirring with a whisk. Heat tortillas according to package directions; keep warm.
Heat a large nonstick skillet over medium heat. Coat pan with cooking spray. Add egg mixture and onion to pan. Cook, without stirring, 2 minutes or until mixture sets on bottom. Draw a spatula across bottom of pan to form curds. (Do not stir constantly.) Cook 2 minutes or until egg mixture is thickened, but still moist. Remove from heat.
Divide egg mixture evenly among warm tortillas. Top with 1/4 cup cheese and 1/4 cup salsa. Fold opposite sides of tortillas over filling; roll up. Serve immediately.
Young Chefs can:
Sprinkle cheese on eggs
Roll up burritos
Older Chefs can:
Combine and whisk first five ingredients