- Lay the steak flat on a rimmed platter or rimmed baking sheet. Combine the lime zest, oregano, coriander, and black pepper; rub it evenly over all the steak and let it sit at room temperature for 30 minutes.
- Prepare your grill so that most of it has a high flame, saving one area for indirect heat (if you have a charcoal grill, leave one area empty; if you have a gas grill, leave one burner off). Cover the lid, allowing the grate to get as hot as possible, preferably up to 600F. Clean the grates well.
- Just before cooking, sprinkle the salt evenly over both sides of the steak, adding less in the thinner areas, and coat it with oil. Grill for about 2 minutes and then, if you want crosshatching, use your tongs to rotate it about 45 degrees. Cook for another 1 to 2 minutes before flipping. Do the same thing on the second side. For a medium-rare steak, figure 7 to 8 minutes total on the grill. Skirt steaks vary in width, so if a thinner steak is cooking faster than the rest, move it to the indirect heat to finish cooking.
- Let the steaks rest for at least 5 minutes. To slice it, first break it down into 4- to 6-inch pieces by making cuts with the grain. Then, thinly slice each one against the grain and on a bias. Serve with Miller Lite-Mustard BBQ Sauce.