COVER NOODLES WITH WATER until soft and pliable, about 15 minutes. Drain. Add noodles to a large pot of boiling water. Reduce to medium heat and cook until noodles are plump and glass-like (2 minutes). For a crunchy texture, just dip them in boiling water for 5 to 10 seconds. Drain and rinse with cold water. Chill. In a large pot of water blanch the shrimp for 5 seconds until they curl and turn pink. Remove and cool. Add oil to a wok or skillet. Add chicken; saute until it loses its pink color. Break into small morsels. Season with salt and pepper to taste. Cool. Mix together chiles, lime juice, nam pla, sugar, shallots and coriander. Add chicken, shrimp and chilled noodles; mix well. Serve over a bed of shredded lettuce. Garnish with crisp fried shallots.