Heat a wok or pan over a high heat, and add the groundnut oil. Add the garlic, and chiles, and stir-fry for a few seconds. Then, add the prawns, rice wine or sherry, and the lime juice, and stir-fry until the prawns start to turn pink.
Add the French beans, and mix together. When the prawns have all turned pink, season with the salt, and chile flakes, and serve immediately.