Prep Ingredients: Slice the bok choy stems into thin pieces, and cut the dark green leaves into strips. Mince half of the ginger and slice the other half into thin matchsticks.
Cook the Noodles: Fill a large pot with salted water and bring it to a boil. Add the rice noodles and cook them according to the package directions. Once cooked, drain the noodles, rinse them under cold water, and set them aside to drain again.
Cook the Pork: Heat 1 tablespoon of peanut or safflower oil in a large skillet over medium-high heat. Add the ground pork, breaking it into small pieces with a fork, and cook until golden and fully cooked, about 10 minutes. Season the pork with ¼ teaspoon kosher salt, 1 ½ tablespoons of soy sauce, and ½ tablespoon of rice vinegar. Remove the pork from the skillet and transfer it to a bowl.
Sauté the Aromatics and Bok Choy: In the same skillet, add the remaining tablespoon of peanut oil. Stir in ¼ cup of the scallions, the finely minced ginger, garlic, and chili slices (if using). Sauté for about 1 minute until fragrant. Then, add the bok choy stems along with ¼ teaspoon salt and cook for 2 minutes, or until they start to soften. Add the bok choy leaves and continue cooking briefly until they wilt. Return the cooked pork to the skillet.
Combine the Noodles and Sauce: Toss the cooked noodles into the skillet, along with ¼ cup of soy sauce and the remaining ½ tablespoon of rice vinegar. Stir the mixture over medium heat until the noodles are heated through. Add the rest of the scallions, sesame seeds, toasted sesame oil, and cilantro. Adjust the seasoning, adding an extra drizzle of sesame oil if desired.
Serve: Transfer the noodle mixture to a serving dish and top with the ginger matchsticks. Drizzle with black vinegar or balsamic vinegar to taste, and serve warm.