If using wooden skewers, soak them in water for 20 minutes to prevent burning during the grilling process.
In a medium-sized glass bowl, whisk together the gochujang, tamari, sesame oil, rice vinegar, honey, grated ginger, and minced garlic until smooth.
Slice the pork loin into uniform 1-inch cubes and toss them into the marinade, ensuring every piece is well-coated.
Prepare the vegetables by chopping the red bell pepper into 1-inch squares and cutting the green onions into 1-inch segments.
Thread the marinated pork cubes onto the skewers, alternating with the bell pepper squares and green onion pieces.
Preheat a grill pan or outdoor grill to medium-high heat and lightly brush the grates with a small amount of oil.
Place the skewers on the grill and cook for 3 to 4 minutes per side, or until the pork reaches an internal temperature of 145 degrees Fahrenheit and the edges are beautifully charred.
Remove the skewers from the heat and sprinkle with toasted sesame seeds before serving warm.