Bring a large pot of water to a boil and cook the soba noodles according to package instructions, adding the baby bok choy during the final 60 seconds of boiling.
While noodles cook, whisk together the tahini, tamari, rice vinegar, coconut sugar, chili oil, and water in a small bowl until the sauce is smooth and emulsified.
Heat the toasted sesame oil in a large skillet or wok over medium-high heat.
Add the ground pork to the skillet, breaking it into small crumbles with a wooden spoon, and cook until browned and no longer pink.
Stir in the minced ginger, minced garlic, and ground Sichuan peppercorns, sautéing for 1-2 minutes until the aromatics are fragrant.
Drain the noodles and bok choy thoroughly and add them directly into the skillet with the pork mixture.
Pour the prepared sesame sauce over the noodles and toss everything together for 1 minute until the sauce thickens slightly and coats the noodles.
Divide into bowls and garnish with thinly sliced green onions before serving.