Spanish chorizo is precooked, so you would only need to break up and warm quickly for a few minutes. Mexican chorizo is raw and needs more time as described below until it reaches a safe 160 degrees F.
If your chorizo has a casing, slice and remove it. Place the chorizo in a large skillet over medium high heat. (There is no need for additional oil.)
With a spoon, or spatula, break it up into small chunks as it cooks. Be sure to stir frequently so that meat does not burn. Continue to cook for 8-10 minutes, or until the meat has more of a brown color (instead of red), and is crumbly (similar to ground beef, but smaller crumbles).
It should no longer be wet or “sticky”. To create tacos: Spoon the cooked chorizo in preferred tortillas and top with chopped onion, shredded cheese and fresh cilantro