Soak wooden skewers in water for at least 20 minutes to prevent them from burning on the grill.
Cut the pork loin and pork belly into uniform 1-inch cubes for even cooking.
In a medium bowl, whisk together the gochujang, tamari, sesame oil, raw honey, minced garlic, and grated ginger.
Reserve two tablespoons of the sauce for the final glaze, then toss the pork cubes in the remaining marinade until well coated.
Slice the zucchini into thick rounds and season them lightly with sea salt and black pepper.
Thread the pork loin, pork belly, and zucchini onto the skewers, alternating the pieces for a balance of textures.
Preheat a grill or grill pan to medium-high heat and lightly brush the grates with a high-heat oil.
Grill the skewers for 4-5 minutes per side, ensuring the pork is cooked through and the belly fat has rendered and charred.
During the last minute of grilling, brush the reserved glaze over the skewers for a glossy, concentrated flavor.
Remove from the heat and garnish with toasted sesame seeds and thinly sliced green onions before serving.