Skirt steak cooked this way has been made nearly famous by one of my favorite personalities, Alton Brown. It's super simple and amazing. Put the skirt steak on a wire rack, sprinkle both sides with kosher salt, let it sit at room temp for an hour, and cook on both sides, directly on hardwood charcoal, for 1 minute each side. Pull it from the fire, and let it rest, well wrapped in foil for 15 minutes. You should have wonderful, Rare to Med-Rare skirt steak.