Slice the pork tenderloin into thin bite-sized strips and the pork belly into very thin small pieces.
Whisk together the gochujang and tamari in a small bowl to create the stir-fry sauce.
Heat a large wok or skillet over medium-high heat. Add the pork belly pieces first, cooking until the fat renders and the edges become golden and crispy.
Add the pork tenderloin strips to the pan, seasoning with sea salt and black pepper. Sear for 3-4 minutes until browned and nearly cooked through.
Push the meat to the sides of the pan and add the sesame oil, minced garlic, and grated ginger to the center. Sauté for 30 seconds until fragrant.
Toss in the chopped bok choy, sliced bell peppers, and snap peas. Stir-fry for 2-3 minutes until the vegetables are tender-crisp and bright.
Pour the gochujang sauce over the mixture and toss everything together for 1 minute until the sauce thickens slightly and coats every ingredient.
Remove from heat and serve immediately in a bowl.