Heat a wok over medium-high heat until smoking. Pour in the peanut oil and swirl in the pan until hot. Stir-fry the garlic, ginger, and fresh green and red chiles until softened, about 1 minute, and then toss in the whole peppercorns and dried chiles and stir-fry briefly to toast.
Pour in the soy sauce, rice vinegar and chili oil, reduce the heat to medium low and bring to a simmer.
Meanwhile, bring a large pot of water to a boil over medium-high heat. Add the zucchini and cook until crisp-tender and bright green, about 30 seconds. Drain the zucchini strips in a colander, shaking well to remove excess water, and then add to the wok along with the cooked noodles. Stir gently until warm and evenly dressed with the fragrant oil.
Transfer the noodles to a serving platter and garnish with cilantro, cracked toasted peppercorns, if using, and a drizzle of sesame oil, if using. Serve immediately.