Bring a large pot of water to a boil and cook the soba noodles according to package directions, adding the baby bok choy during the last 60 seconds of cooking to blanch.
Drain the noodles and bok choy, then rinse briefly under cold water to stop the cooking process and prevent sticking.
In a small bowl, whisk together the tahini, tamari, rice vinegar, chili oil with flakes, Sichuan peppercorn powder, and water until the sauce is smooth and creamy.
Heat the toasted sesame oil in a large skillet or wok over medium-high heat; add the minced ginger and garlic, sautéing for 30 seconds until fragrant.
Add the ground pork to the skillet, breaking it up with a spatula and browning it thoroughly until fully cooked and slightly crispy.
Add the cooked noodles, bok choy, and prepared sauce to the skillet with the pork, tossing everything together for 1-2 minutes until heated through and well-coated.
Divide the mixture into a bowl and garnish with sliced green onions before serving.