Preheat a charcoal or gas grill with greased grill rack for direct cooking over medium heat (350°).

Whisk together gochujang sauce, brown sugar, soy sauce, and garlic and ginger pastes in a small bowl. Coarsely chop 4 green onions; stir into sauce mixture. Set aside.

Pat pork chops dry with paper towels. Open each chop. Place each chop between 2 pieces of plastic wrap. Using the flat side of a meat mallet, lightly pound chops to ½-inch thickness.

Remove plastic wrap. Coat both sides of chops with sauce mixture. Place kimchi evenly on top of one half of each butterflied chop. Fold the other side of the pork chop up and over the kimchi. Secure with toothpicks or kitchen string.

Grill chops 12 to 18 minutes or until pork reaches 165°, turning halfway through. Remove from grill; loosely cover with foil and let rest 3 minutes.

Lightly spray remaining 8 green onions with nonstick spray. Grill 1 to 2 minutes or until lightly charred, turning halfway through. Remove from grill. Serve chops with grilled green onions.