Heat oil in a large heavy skillet over medium heat. Fry chorizo until browned. Drain off any excess oil. Add onion and cook 2 to 3 minutes, then add the chiles. Beat eggs until frothy and add to the chorizo. Stir with a fork as you would scrambled eggs. Fold cilantro in just before the eggs set.
Serve with flour tortillas, fresh salsa, and mashed avocado.