Soak wooden skewers in water for at least 20 minutes to prevent burning on the grill.
Cut the pork tenderloin into 1-inch cubes and chop the bell peppers and red onion into similarly sized pieces.
In a medium bowl, whisk together the gochujang, coconut aminos, toasted sesame oil, raw honey, rice vinegar, minced garlic, grated ginger, sea salt, and black pepper.
Add the pork cubes to the bowl and toss thoroughly to coat, then let marinate for 15 minutes at room temperature.
Thread the marinated pork, bell peppers, and red onions onto the skewers, alternating between meat and vegetables.
Preheat a grill or cast-iron grill pan over medium-high heat and lightly grease with a high-smoke point oil.
Grill the skewers for 3 to 4 minutes per side, turning occasionally, until the pork is cooked through and the edges are beautifully caramelized.
Remove from heat and garnish with toasted sesame seeds and thinly sliced green onions before serving.