Soak wooden skewers in water for 20 minutes to prevent burning during grilling.
Cut the pork tenderloin, pork belly, zucchini, and red bell pepper into uniform 1-inch cubes.
In a small bowl, whisk together the gochujang, tamari, toasted sesame oil, honey, minced garlic, and grated ginger.
Toss the pork cubes in the marinade until well coated, then season with sea salt and black pepper.
Thread the pork and vegetables onto the skewers, alternating between the lean tenderloin and the flavorful belly pieces.
Heat a grill pan or outdoor grill to medium-high heat and lightly oil the grates.
Grill the skewers for 3-4 minutes per side until the pork is cooked through and the belly edges are crispy.
Brush with any remaining marinade during the final minute of cooking for a glossy, spicy finish.