Slice pork chops thinly against the grain into 1/4-inch strips. In a bowl, combine pork with soy sauce, cornstarch, and sesame oil. Marinate for 15 minutes at room temperature.
In a small bowl, whisk together soy sauce, oyster sauce, hoisin sauce, sesame oil, sugar, and white pepper. In a separate small bowl, mix cornstarch with cold water to make a slurry.
Prep all vegetables by thinly slicing bell pepper and onion, cutting broccoli into bite-sized florets, and trimming snap peas. Mince garlic and grate ginger.
Heat a wok or large skillet over high heat until smoking. Add 2 tablespoons oil and sear marinated pork in a single layer for 1-1.5 minutes per side until golden and cooked through. Remove and set aside.
Return wok to high heat and add remaining oil. Stir-fry onion and bell pepper for 2 minutes, then add broccoli and snap peas and cook for 2 more minutes until bright and crisp-tender.
Push vegetables to the sides, add garlic and ginger to the center, and cook for 30 seconds until fragrant. Return pork to the wok, pour in sauce, and toss to coat evenly.
Stir cornstarch slurry and add to wok while tossing. Cook for 60 seconds until sauce thickens and turns glossy. Remove from heat, garnish with green onions and sesame seeds, and serve over rice or noodles.