Soak wooden skewers in water for at least 20 minutes to prevent burning.
Cut the pork tenderloin and pork belly into uniform 1-inch cubes.
In a medium bowl, whisk together the gochujang, tamari, sesame oil, honey, grated ginger, and minced garlic.
Add the pork cubes to the bowl and toss until thoroughly coated; let marinate for 15 minutes.
Thread the pork onto the skewers, alternating between the lean tenderloin and the rich pork belly pieces.
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 a nice charred glaze.
While the pork cooks, toss the sliced cucumbers with rice vinegar, sea salt, and black pepper in a small bowl.
Serve the hot skewers over the chilled cucumber salad and garnish with sesame seeds and sliced green onions.