Whisk the gochujang paste, tamari, rice vinegar, minced garlic, and grated ginger in a small bowl until the glaze is smooth.
Dice the pork belly into small cubes and slice the pork tenderloin into thin strips to ensure even cooking.
Heat the sesame oil in a large skillet over medium-high heat until it begins to shimmer.
Add the pork belly to the skillet first, sautéing until the fat renders and the edges become golden and crispy.
Add the pork tenderloin strips to the pan, searing them in the rendered fat for 3-4 minutes until fully cooked.
Pour the gochujang glaze over the meat and toss for 1 minute until the sauce reduces into a thick, sticky coating.
Steam the cauliflower rice and lightly sauté the chopped bok choy in a separate pan until tender-crisp.
Divide the cauliflower rice into bowls, top with the spicy pork mixture and kimchi, then garnish with sesame seeds and sliced green onions.