Cut the beef into strips. Coat with cornstarch diluted in 1 tablespoon of sesame oil. Add the minced lemongrass and lime juice. Place in refrigerator for 30 minutes. Wash and trim the snow peas. Bring water to a boil in a saucepan and immerse the noodles. Cook according to the cooking time indicated on the packaging. Drain them and stir in a tablespoon of sesame oil. Set aside. Heat 1 tablespoon of peanut oil in a sauté pan or wok. Put the beef strips with the marinade. Cook 1 minute, stirring constantly. Remove the meat and cooking juice. Set aside. Put 1 tablespoon of oil in the wok and add the ginger and garlic then the snow peas. Let cook for approximately 2 minutes. Stir in the noodles, beef strips and cooking juice. Mix together while continuing to cook for 1 to 2 minutes. Season with parsley and coriander. Serve immediately