Cut the pork loin into uniform 1-inch cubes and set aside.
In a small bowl, whisk together the gochujang, tamari, sesame oil, honey, grated ginger, and minced garlic until smooth.
Place the pork cubes in a bowl and toss with half of the gochujang mixture to coat thoroughly.
Thread the marinated pork onto wooden or metal skewers.
Preheat a grill or grill pan over medium-high heat and lightly oil the surface.
Grill the skewers for 8-10 minutes, turning occasionally and brushing with the remaining glaze until the pork is cooked through and slightly charred.
While the pork grills, toss the sliced cucumbers with rice vinegar and red pepper flakes in a small bowl.
Remove the skewers from the heat, sprinkle with sesame seeds, and serve immediately with the cucumber salad.