In a small bowl, whisk together the gochujang, tamari, sesame oil, honey, minced garlic, and grated ginger to create a thick glaze.
Cut the pork tenderloin and pork belly into 1-inch cubes, then slice the zucchini into thick rounds and the bell pepper into squares.
Place the pork and vegetables in a large bowl, season with sea salt and black pepper, and toss with half of the gochujang glaze.
Thread the pork and vegetables onto skewers, alternating between the lean tenderloin, the rich pork belly, and the fresh produce.
Heat a grill pan or outdoor grill over medium-high heat and cook the skewers for 3-4 minutes per side until the pork is cooked through and the edges are beautifully charred.
Brush the remaining glaze over the hot skewers during the last minute of cooking for a glossy, spicy finish.
Remove from heat and garnish with toasted sesame seeds and thinly sliced green onions before serving.