Cook the noodles according to the package directions. Drain the noodles and toss with the sesame oil and set aside. In a medium bowl, whisk the eggs with the brown sugar and a generous pinch of salt. In a small bowl, whisk together the soy sauce, rice vinegar, peanut butter and Sriracha hot sauce.

Heat 2-3 tablespoon of the neutral oil in a wok over high heat until shimmering and hot. Add the garlic cloves and piece of ginger and stir-fry until fragrant, 10-12 seconds. Remove and discard. Add in the steamed asparagus pieces and stir fry 2-3 minutes. Transfer asparagus to a bowl. Pour the eggs into the wok and scramble until softly set, 1 to 2 minutes. Transfer to the bowl with the asparagus. Add more oil if needed. Place the noodles in the wok, add the soy/vinegar mixture, and toss with tongs or a spatula until coated, about 1 minute or so. Add the eggs and vegetables back into the wok and toss until heated through, about 2 minutes more. Remove from the heat, and toss with the scallions, lime juice and peanuts, if using.