To make the sauce: In a bowl, pour the boiling water over the brown sugar and stir to dissolve. Add the lime juice, fish sauce, rice vinegar, and sriracha and stir. Place the leftover turkey in the pad Thai sauce and let it absorb the flavors while prepping the rest of the dish. Next, prepare the pasta: cook the linguine one minute less than the manufacturer's directions. Drain, and set aside.
Heat the oil in a wok or large saute pan over high heat until very hot, almost smoking. Add the onions and stir fry 1 minute. Add the garlic and stir. Then add the eggs and cook for 30 seconds, stirring. Add the linguini and turkey with sauce and cook, stirring for a few minutes. Remove from heat and toss in grated carrot, peanuts, cilantro, bean sprouts and scallion. Serve with lime wedges, if desired.