Place the skirt steak on a plate or cutting board and sprinkle generously with Kosher salt and fresh ground black pepper on both sides.
Rip off two layers of aluminum foil, enough to wrap the skirt steaks. You'll need it as soon as the steaks come off of the grill so have it close by.
Leave the skirt steak on the counter at room temperature for at least 20 minutes, up to an hour, or until the fire is ready.
Light your grill and get the fire as hot as it will go. For gas grills, turn on the sear burner and close the lid to heat for 15 minutes on high. For charcoal grills, open all of the vents, get the grate as close to the coals as possible and let it get as hot as you can get it.
Once the grill is really hot, place the skirt steaks over the hottest part of the fire. We are looking for a quick sear, as much fire as possible, so let it flare up.
Grill the skirt steak for ONLY 1 - 2 minutes on each side, just enough to get a nice dark sear.
Immediate wrap the grilled skirt steaks in the double layer of aluminum foil, sealing it tightly.
Let the skirt steaks rest in the foil for 10 - 15 minutes.
Unwrap the steak and cut thinly, against the grain and serve.