Parboil the pork in a little water until easier to slice. Let cool slightly, then slice thinly.
Clean the mushrooms and slice into large bite-size pieces.
Slice the chili peppers, then remove the seeds and membranes. For less heat, blanch briefly in boiling water.
Mix the soy sauce, oyster sauce, Shaoxing wine, sugar, cornstarch, and water.
Brown the pork over medium-high heat until lightly crisp. Season with salt and pepper, then set aside.
Sear the mushrooms over medium-high heat until lightly browned, then set aside.
Sauté the ginger until lightly golden. Add the onion and garlic, then cook until lightly browned.
Add the chili peppers and cook for a few minutes. Add the white parts of the scallions and cook just until tender.
Add the pork, mushrooms, and sauce. Toss until coated and thickened. Add more water if needed.
Add the green parts of the scallions and ground pepper. Toss together, then turn off the heat.