Cook the soba noodles in boiling water according to package directions, adding the chopped baby bok choy during the last 60 seconds of cooking.
Drain the noodles and bok choy, then set aside.
In a small mixing bowl, whisk together the sesame paste, tamari, chili oil, sesame oil, and rice vinegar until a smooth sauce forms.
Heat a large non-stick skillet over medium-high heat and add the ground pork, breaking it apart with a spatula until browned and cooked through.
Stir in the minced ginger, minced garlic, and crushed Sichuan peppercorns, sautéing for 1 minute until highly fragrant.
Add the cooked noodles, bok choy, and the prepared sauce to the skillet, tossing continuously for 1-2 minutes until everything is evenly coated and hot.
Divide into a bowl and garnish with thinly sliced green onions before serving.