Bring 4 quarts of water to a boil. Turn off the heat. Add the rice sticks and let them soak for 5 minutes. Drain noodles and rinse with cold water. Set aside. Heat oil in wok, add mustard seeds and fry until they crackle. Add black lentils and cashews. Stir fry for 1 minute. Add red chiles, yellow lentils, green chiles, ginger and turmeric. When cashew nuts have darkened add the cooked noodles. Toss well for 2 minute to heat the noodles. Remove from heat, add lemon juice and cilantro. Season with salt. Toss well to combine. Cover, set aside for 4 minutes. Serve with lemon wedges.