Bring a pot of water to a boil for the noodles and cook noodles to just tender, but they still have a bite. Reserve half a cup of starchy water; drain.
Heat peanut oil in a wok-shaped pan or large, deep skillet over medium-high heat. Stir in garlic and ginger 1 minute then add sherry, stock, soy, peanut butter, light brown sugar and Sichuan peppercorn. Add reserved starchy water and noodles, and toss 1 minute. Remove from heat and toss with chili oil.
Top the bowlfuls of noodles with peanuts, scallions and sesame seeds and serve. Serve hot or chilled.