Heat oven to 350°F.
Spray 11x7-inch (2-quart) glass baking dish with cooking spray.
In medium bowl, mix shredded cheese, zucchini and cilantro.
Spread about 2 teaspoons cream cheese on each tortilla.
Top each with about ⅓ cup shredded cheese mixture to within 1 inch of edge.
Roll up tortillas; place seam side down in baking dish.
Pour salsa over enchiladas.
Cover with foil.
Bake about 25 minutes or until hot.
Top with avocado and onions before serving.