Fry the curry paste: In a wok or large pot, turn heat to medium. When wok is hot but not smoking, add 2 tbl curry paste and the lemongrass (or lemon peel). Fry for 30 seconds to release its flavors. Add the clam juice, fish sauce, sugar and coconut milk. Simmer for 3 minutes. If you are using lemon peel, discard lemon peel. Taste the broth. If you want more heat, add more curry paste. In meantime, drain your mung bean noodles. The noodles should still be a little stiff.