In this popular Thai dish, chewy noodles are paired with crunchy vegetables.
Soak noodles in warm water for 20 minutes, or until softened; drain well. Meanwhile, combine 1/4 cup water, sugar, vinegar, fish sauce, tamarind mixture, and dried chiles in a small saucepan. Simmer, stirring, for 5 minutes. Remove from heat, add dried shrimp, and set aside.
Heat oil in a large nonstick skillet or wok over medium heat. Add shallots and garlic, and stir-fry for 2 minutes. Stir in sugar mixture, and reduce heat to lowest possible setting. Bring a medium saucepan of salted water to a boil. Add string beans, and cook for 1 1/2 minutes. Add sugar-snap peas, and continue cooking for 30 seconds. Drain, and set aside.
In another large nonstick skillet, cook shrimp over medium-high heat, 3 minutes per side. Meanwhile, add noodles, a quarter of the bean sprouts, and half the scallions to the shallot mixture. Raise heat to high, and boil, stirring, for 2 minutes. Add shrimp, string beans, and sugar-snap peas, and stir for 1 minute more. Turn out noodles onto a platter, sprinkle with peanuts and remaining scallions, and arrange lime quarters, coriander sprigs, and remaining bean sprouts beside them.