In a small bowl, whisk together the gochujang, tamari, toasted sesame oil, rice vinegar, raw honey, minced garlic, and grated ginger until smooth.
Cut the pork tenderloin and pork belly into 1-inch cubes and season them lightly with sea salt and black pepper.
Cut the scallions into 1-inch pieces, using both the white and firm green parts.
Thread the pork tenderloin, pork belly, and scallion pieces onto skewers, alternating the lean meat with the fatty belly for maximum flavor.
Generously brush the skewers on all sides with the gochujang marinade, reserving a small amount for a final glaze.
Heat a grill pan or outdoor grill to medium-high heat and cook the skewers for 8-10 minutes, turning frequently until the meat is cooked through and the edges are beautifully charred.
Remove the skewers from the heat, brush with the remaining glaze, and garnish with sesame seeds before serving hot.