Slice the pork tenderloin into very thin, bite-sized strips and season with sea salt and black pepper.
In a small glass bowl, whisk together the gochujang, tamari, toasted sesame oil, rice vinegar, honey, minced garlic, and grated ginger to create the stir-fry sauce.
Heat a large non-stick skillet or wok over medium-high heat. Once hot, add the pork strips in a single layer and sear until golden brown and cooked through, about 3-4 minutes.
Remove the pork from the pan and set aside. In the same pan, add the broccoli florets and sliced red bell peppers with a splash of water, covering for 2 minutes to steam-sauté until tender-crisp.
Return the pork to the pan and pour the gochujang sauce over the meat and vegetables.
Toss everything together for 1-2 minutes until the sauce thickens and glazes the ingredients evenly.
Serve the spicy pork and vegetable mixture over the warm cooked brown rice and garnish with fresh sliced green onions.