Bring a pot of water to a boil and cook the soba noodles according to package directions, adding the baby bok choy during the last minute of cooking.
Drain the noodles and bok choy, then set aside.
In a small bowl, whisk together the tahini, tamari, rice vinegar, chili oil, and toasted sesame oil until smooth.
In a large skillet over medium-high heat, cook the ground pork until browned and crumbled, about 5-7 minutes.
Add the grated ginger, minced garlic, and crushed Sichuan peppercorns to the skillet, sautéing for 1 minute until fragrant.
Add the noodles, bok choy, and prepared sauce to the skillet, tossing everything together until well-coated and heated through.
Serve immediately topped with sliced green onions.