Cut the pork tenderloin into 1-inch cubes and place them in a glass mixing bowl.
In a small jar, whisk together the gochujang, coconut aminos, toasted sesame oil, grated ginger, and minced garlic until the marinade is well combined.
Pour half of the marinade over the pork cubes, tossing to ensure every piece is coated, and let it marinate for 15 to 20 minutes.
Slice the red bell pepper and zucchini into chunks that are roughly the same size as the pork cubes.
Thread the marinated pork, bell pepper, and zucchini onto skewers, alternating the meat and vegetables for even cooking.
Season the assembled skewers lightly with sea salt and black pepper.
Heat a grill pan or outdoor grill to medium-high heat and lightly coat with a high-smoke point oil like avocado oil.
Grill the skewers for 3-4 minutes per side, brushing with the remaining marinade during the final minutes of cooking until the pork is cooked through and slightly charred.
Remove from the heat and garnish with toasted sesame seeds and thinly sliced green onions before serving.