On its most basic level, Carne Asada is a marinated and grilled steak, sliced thin and served on tortillas. This "grilled beef" can be used however you want it, in tacos, burritos or served up straight. The basic method is to marinate most any kind of beef in a lime based marinade. Grill it over a hot fire and then slice into thin strips across the grain. But there is a whole lot more to it than that.
Tradition: In Mexico and the American Southwest you will find that Carne Asada is the Mexican equivalent of Barbecue. I mean that in the party sense of the word. Traditionally a large fire pit is used to prepare this party but you can use whatever you have. Since everything is prepared over direct heat you don't need a lid or a fancy grill. The cut of beef you use doesn't need to be fancy either. Traditionally Carne Asada is made from Skirt Steak. You want a flavorful cut that doesn't need to be tender so if you can't get Skirt Steak go with a Flank Steak or even trimmed Brisket cut into 1 inch thick "steaks". If you are planning on a big party and want to have plenty for everyone plan on about 1 pound of meat per person. Of course, if you have lots of side dishes then cut back on the meat.
Marinade: Marinating is not necessary but it will add flavor and tenderness to your meat. A good marinade for Carne Asada will have lots of lime juice, garlic, onion and black pepper. Of course other fruit juices work great as well, especially papaya which really makes meat tender since it is a source of natural tenderizers. You can add hot peppers to the marinade if you want but be careful you don't over power the meat and make it too hot to handle. Don't add salt to your marinade.
Seasoning: Ideally the meat should be cooked over a charcoal fire. Traditionally mesquite is used, or course. Wood chips in a smoker box will help, but nothing beats the authentic flavor of a real fire. When you get ready to grill you will want to have salt on hand. Use a good coarse salt and add some cumin, powdered garlic and whatever else you like to the salt. Shake it up good and keep it on hand. You want to grill over a good, hot fire. This dish cooks pretty quickly so have everything else out of the way when you start.
Grilling: Place the meat on the grill and when the juices start to rise on the surface, sprinkle with the salt. When the salt liquefies on the surface flip the meat over and repeat. This seasons the meat as it cooks. Carne Asada is supposed to be on the salty side but this doesn't mean that you need to drown the meat in salt. This sprinkling is also the reason you don't want to use a marinade with salt.
Traditionally Carne Asada is grilled to well done. Most people who didn't grow up eating this dish might find that a little hard to swallow so I usually work towards a medium. Once you have the meat grilled to perfection you will want to take it straight to a carving board. Cut the meat across the grain with a good sharp knife. The pieces should be thin strips. Keep the meat warm in a heavy pot with a lid. You don't need to add heat but you want to hold in the heat you have.
Serving: Serve with warm tortillas and whatever fixings you prefer. A good Carne Asada taco would be topped with salsa, chopped red onion, guacamole, salt and lemon juice. Now that’s a taco. If you have leftovers, make enchiladas the next day. Oh, and serve with lots of your favorite cold beverage.