This is a wonderfully flavorful dish that can be easily prepared in a pinch. If you cannot find the kaffir lime leaf, omit it (although it adds nice flavor). You can also use standard string beans instead of the long beans. Make sure to cook the dish on as high a heat as possible so that the chicken sears quickly and doesn't dribble out all its juices in the pan. I recommend cooking only 1 lb of chicken at a time so you don't overcrowd the pan. My recipe is based off of the one here at Eating Thai Food.
1 lb chicken breast, cut into 3/4" slices
1/2 c. Chinese long beans, cut into 1/4" slices (or string beans)
3 Tbsp. Thai red curry paste
1 Tbsp. fish sauce
1 tsp sugar
4 kaffir lime leaves, chiffonade
2 Tbsp. peanut oil
Heat a flat bottomed wok on medium high and then add the oil. Add the curry paste and stir/chop with a wok spoon or spatula so that it sizzles and softens for 30 seconds. Ensure it does not burn.
Add the chicken, fish sauce, and sugar and toss over high heat for 4-5 minutes, until the chicken is mostly cooked through. Add in the lime leaf and long beans and continue to toss and cook an additional 3-4 minutes. The beans will be crisp in texture.
Serve with jasmine rice and a fried egg. In Thailand the eggs are traditionally fried in a wok so the edges are crispy and the yolks are cooked through. Enjoy!