Cut the kimchi and pork into bite-sized pieces.
Cut the tofu, green onion, and onion into appropriate sizes.
Heat cooking oil in a pot and stir-fry the pork.
Add the kimchi and stir-fry together.
Pour in water and kimchi juice.
Add gochujang (Korean red chili paste), minced garlic, soy sauce, and pepper. Bring to a boil.
Add tofu, onion, and green onion, then simmer for another 5 minutes.
Taste and season with salt if needed.