Whisk the cola, cilantro, soy sauce, sesame oil, vinegar pepper and garlic in a large baking dish. Add the pork and turn to coat. Cover the baking dish and marinate in the refrigerator for at least 2 hours and up to 8 hours.
Prepare the grill for indirect grilling, with part of the grill at high heat. Remove the pork from the marinade 30 minutes before grilling to take the chill off.
Grill the pork until charred, about 3 minutes. Flip the pork and grill for another 3 minutes. Both sides of the pork should be nicely charred. Move the pork to indirect heat, cover the grill, and cook for about 5 minutes until a meat thermometer inserted in the pork registers 150 degrees F. Remove the pork from the grill and set aside, loosely tended with foil, about 10 minutes.
Cut the pork, against the grain, into thin strips. Fill the lettuce leaves with some of the pork, a drizzle of the Gojuchang Sauce and top with the Quick Kimchi.
Put the cabbage in a large bowl. Make an ice bath in a larger bowl.
Combine the vinegar, fish sauce, gochujang, honey, ginger, garlic and chiles in a small saucepan. Bring the mixture to a simmer and immediately pour over the cabbage. Set the bowl of cabbage in the ice bath and cool, tossing occasionally. When the cabbage is cool, add the cilantro and onions.
Whisk the gochujang, soy sauce, vinegar, honey, seeds, sesame oil, garlic and onions in a small bowl.