1 large bok choy (about 2 pounds), trimmed, cut crosswise into 1-inch strips, and washed (with some water still clinging to leaves)
4 scallions thinly sliced, white and green parts separated
4 cloves garlic sliced
1 piece (about 2 inches) fresh ginger peeled and minced
In a large bowl of hot tap water, soak noodles until soft, 10 to 15 minutes; drain and set aside. Meanwhile, make sauce: In a small bowl, whisk together soy sauce, vinegar, sugar, sesame oil, and red-pepper flakes; set aside.
In a large skillet with a lid, heat oil over medium-high. Season pork chops with salt and pepper. Place in skillet, and cook, turning once, until opaque throughout, 3 to 4 minutes per side. Transfer chops to a plate; loosely cover with aluminum foil, and set aside.
To skillet, add bok choy, scallion whites, garlic, and ginger. Cover and cook, tossing occasionally, until bok choy stems are crisp-tender, 4 to 5 minutes.
Add noodles and sauce from step 1. Cook, tossing gently, until noodles are heated through, 2 to 3 minutes.
Thinly slice pork chops. Serve on top of noodles, and sprinkle with scallion greens.