Trim any excess fat from the pork shoulder and cut into 1-inch cubes.
In a small glass bowl, whisk together the gochujang, tamari, rice vinegar, sesame oil, grated ginger, and minced garlic.
Place the pork cubes in a resealable bag or bowl and pour the marinade over them, tossing to coat evenly. Let marinate for at least 20 minutes.
Cut the red bell pepper into 1-inch squares to match the size of the pork.
Thread the marinated pork and bell pepper squares onto wooden or metal skewers, alternating between meat and vegetable.
Season the assembled skewers lightly with sea salt and black pepper.
Preheat a grill or grill pan to medium-high heat and lightly oil the grates.
Grill the skewers for 3-4 minutes per side, or until the pork is cooked through and has developed a deep, charred glaze.
Remove from the heat and let rest for 2 minutes before serving.