Cook the noodles according to the package directions, then drain and set aside.
Prepare the sauce. In a small bowl, whisk together the vinegar, sugar, soy sauce, fish sauce (if using), and hot sauce. Set aside.
In a large nonstick skillet or wok, heat 1 tablespoon of oil over medium-high heat. Add the shrimp and stir-fry until they turn pink. Remove the shrimp from the skillet and set aside.
In the same skillet, add the remaining 1 tablespoon of oil. Add the chopped onion and minced garlic, and stir-fry until fragrant.
Push the onion and garlic to the sides of the skillet, creating a well in the center. Crack the egg into the well and scramble it until fully cooked.
Add the coleslaw mix and sliced green onions to the skillet. Mix everything together.
Pour the sauce mixture over the coleslaw and egg mixture in the skillet. Stir-fry until everything is heated through.
Return the cooked shrimp to the skillet and mix everything together.
Add the cooked noodles to the skillet and gently toss them with the other ingredients.
Divide the Pad Thai mixture between two serving plates. Sprinkle chopped peanuts over each serving and garnish with fresh cilantro leaves.