In a small bowl, whisk together the gochujang, tamari, toasted sesame oil, honey, rice vinegar, minced garlic, and grated ginger until smooth.
Cut the pork tenderloin into 1-inch cubes and place them in a bowl; pour half of the marinade over the pork and toss to coat thoroughly.
Prepare the vegetables by cutting the red bell pepper and green onions into 1-inch pieces suitable for skewering.
Thread the marinated pork, bell peppers, and green onions onto skewers, alternating between the meat and vegetables.
Heat a grill pan or outdoor grill over medium-high heat and lightly grease with a small amount of avocado oil if necessary.
Grill the skewers for 3 to 4 minutes per side, or until the pork is cooked through and the vegetables have a nice charred edge.
During the last minute of cooking, brush the remaining marinade over the skewers for a glossy, flavorful finish.
Serve the hot skewers over a bed of cooked white rice and garnish with a sprinkle of toasted sesame seeds.