In a large glass baking dish whisk together Carne Asada marinade ingredients (jalapeño through black pepper) until combined. Add skirt steak in a single layer, turning to coat with marinade. Cover and refrigerate for at least 1 hour, but no longer than 8 hours (longer will begin to break down the meat).
When you're ready to grill: preheat an outdoor grill to medium-high heat. Grill steaks for 7 to 10 minutes per side, turning once for medium-rare. Remove steaks and allow to rest for 5 minutes.
Slice thinly across the grain and serve.
Ask your butcher or grocery meat counter for 'outside skirt steak' for the most flavorful and juicy results.
Note that the longer you marinate the skirt steak, the more tender and flavorful it will be come. But be sure to grill it within 8 hours to maintain the texture of the meat.