Bring a large pot of water to a rolling boil and cook the soba noodles according to the package instructions, adding the chopped bok choy during the final 60 seconds of cooking.
Drain the noodles and bok choy thoroughly in a colander and set them aside.
In a large non-stick skillet over medium-high heat, cook the ground turkey until it is completely browned and no pink remains, using a spatula to break it into fine crumbles.
Add the minced garlic, grated ginger, and ground Sichuan peppercorns to the skillet, sautéing for about 1 minute until the mixture becomes highly fragrant.
In a small mixing bowl, whisk together the tahini, tamari, rice vinegar, chili oil, and sesame oil until the sauce is smooth and emulsified.
Transfer the cooked soba noodles and bok choy into the skillet with the turkey mixture.
Pour the prepared sauce over the ingredients and toss everything together with tongs until the noodles are evenly coated and the dish is heated through.
Divide the mixture into bowls and garnish with the freshly sliced green onions before serving.