The tangy and spicy gochujang marinade caramelizes on the steak as it cooks. It’s complemented by the refreshing scallion and charred shishito salsa served over the top.
Heat a large cast-iron skillet or other heavy bottom sauté pan over medium-high heat, add olive oil and heat through so the oil is very hot but not yet smoking.
Add the peppers and sauté, turning occasionally until tender and blistered on all sides, about 3 minutes.
Remove and chop the shishitos. Stir together in a medium bowl with the scallions and sesame seeds.
In a small bowl whisk together the gochujang, vinegar and oil until combined. Add the skirt steak and gochujang mixture to a large resealable plastic bag. Let the steak marinate, refrigerated, for at least 1 hour and up to overnight.
Heat a gas grill or large cast iron pan over medium-high heat. Remove the steak from the marinade, wiping off any excess.
Add the ribeyes to the grill or pan and sear, for 4 minutes. If grilling, keep an eye out for flare-ups. If a flare-up occurs and lasts for more than a few seconds, move the steaks out of the fire to prevent overcooking the steak.
Flip and cook the steaks until medium-rare, about an additional 4 minutes. The internal temperature of the steak should be 130ºF (54ºC) for medium-rare.
Remove from the grill and let the meat rest on a cutting board for about 15 minutes.
Slice the steak and serve topped with the scallion shishito salsa.