Step 1In a blender, combine the cilantro, garlic, onion, Worcestershire, optional chiles and a teaspoon of salt, or to taste. Blend the ingredients to make the marinade, and rub the marinade all over the meat. Place the meat in a large, sealable plastic bag or in a large baking dish covered with plastic wrap, and refrigerate for at least 1 hour, up to several hours, to marinate.
Step 2Shortly before cooking, heat a grill over medium-high heat until hot. Oil the grill then add the carne asada (this will probably need to be done in batches). Cook the meat for a minute or two on each side to char the meat and then cook to desired doneness. Repeat with all of the carne asada. Serve hot.