Cut the pork loin into 1-inch cubes and set aside in a medium mixing bowl.
In a small jar, whisk together the gochujang, tamari, sesame oil, honey, minced garlic, and grated ginger until smooth.
Pour half of the gochujang marinade over the pork cubes, tossing to coat thoroughly, and let marinate for at least 15 minutes.
While the pork marinates, chop the red bell pepper and red onion into 1-inch pieces suitable for skewering.
Thread the marinated pork, bell pepper, and red onion onto skewers, alternating between meat and vegetables.
Brush the assembled skewers with avocado oil and season lightly with sea salt and black pepper.
Preheat a grill or cast-iron grill pan over medium-high heat and cook the skewers for 3 to 4 minutes per side until the pork is cooked through and the edges are slightly charred.
Remove from heat and brush with the remaining gochujang glaze before serving warm.