In a large skillet, saute onion in margarine. Stir in flour, and cook on low for 1 minute stirring constantly. Add milk and cream and cook on medium heat stirring until mixture has thickened. Add green chile, salt, pepper. Remove sauce from heat, and set aside. In In another skillet, scramble eggs lightly and add ham. Remove from heat. In a small bowl, mash the avocados, and sprinkle with a dash of salt. Spread out all tortillas on counter, and spoon 2 tablespoons of the sauce, 1/8 of the eggs, and 1/8 of the avocados on each tortilla Roll up and place seam side down on a greased 9×13 inch baking dish Spoon remaining sauce over the tortillas Bake covered at 325 degrees for 25 minutes or until tortillas are hot and bubbly. Remove from oven, sprinkle cheese over top and return to oven for 10 minutes. When serving, top each tortilla with a dab of salsa.