Prepare the rice noodles following the packet directions. Drain and set aside. Meanwhile, combine the tamarind puree, fish sauce, palm sugar, soy sauce and lime juice. Set aside. Heat a wok or large non-stick frying pan over high heat. When hot, add the oil. Add the garlic and chilli and stir fry for 10 seconds or until aromatic. Add the chicken and stir fry for 2 minutes or until it is almost cooked through. Add the prawns and stir fry for 2 minutes or until they change colour. Add the drained noodles and tamarind mixture and stir fry for 30 seconds. Push the noodles to one side of the wok or pan then pour the egg into the space. Let it sit for 30 seconds to cook slightly then stir fry for a further minute. Stir in the bean sprouts and garlic chives.