For the Ancho Chile Sauce, wipe outside of chilis with damp paper towel to remove any dust. Place chilis, water, onion and garlic in medium saucepan. Bring to boil. Reduce heat; cover and cook 10 minutes until chilis are softened.
Carefully transfer chili mixture to blender container. Add vinegar, oregano, salt and pepper. With center part of lid removed, blend until smooth. Transfer mixture to medium bowl. Set aside.
For the Enchiladas, place boiling water in large heat-proof bowl. Stir in salt until dissolved. Add zucchini and let stand 1 minute. Drain well; set aside.
Heat 1 tablespoon of the oil in large skillet. Add chorizo; cook 5 minutes until browned. Remove with a slotted spoon; set aside. Do not drain oil from skillet.
Add remaining 2 tablespoons oil to skillet; heat until shimmering. Dip 1 tortilla in Ancho Chile Sauce to coat, shaking gently to remove excess. Place in hot skillet. Cook 1 minute per side until softened. Repeat with remaining tortillas.
To serve, fill hot tortillas with chorizo, zucchini, shredded lettuce, radishes and crumbled Cotija.