Make marinade. In a large mixing bowl, add grated pear and grated onion. Add minced garlic and ginger, Add gochujang paste, gochukaru, soy sauce, sugar, mirin, sesame oil, and black pepper. Mix with a spoon until well combined.
Marinate pork. Add thinly sliced pork and using your hands, mix well until the pork is coated with the marinade.
Cook pork. Heat the wok on medium-high heat. When the wok is hot, add 1-2 Tbsp oil. Swirl to coat the bottom of the wok. Add the marinated pork and lightly spread out into a thin layer. Leave the pork undisturbed, for 1-2 minutes, to get a good sear on one side. Cook, stirring with a long-handled metal spatula, until pork is cooked through, about 5-6 minutes.
TIP: Cook the pork in batches, making sure not to crowd the pan. Transfer the cooked pork onto a plate and then wipe down the wok with a paper towel before cooking the next batch.
Note: Make sure to cook long enough. The pork will release a lot of liquid and needs to be reduced and caramelized. Keep cooking until the sauce darkens and thickens. The sauce should not be watery but should be thick enough to cling to the pork.
Add cabbage and onion. Move the pork to the side and add the cabbage and onion. Stir together until the cabbage and onion are wilted, about 1-2 minutes. Add the previously cooked pork as well, if cooking in batches. Stir well to combine and scrape down the sides of the wok.
Add green onion. Add the green onion and continue cooking until wilted, another 1-2 minutes.Serve. Transfer to a serving platter. Serve immediately with rice, kimchi, and lettuce wraps. Enjoy!