Heat 1T oil in a non-stick pan. Add 1T lemongrass (paste or chopped fresh) and 3 dried chilies. Stir to combine. Add green beans and cook about 2 minutes, stirring to cook evenly. Turn off heat and stir in kaffir lime zest*. Serve.
*If you can't find kaffir limes, which look like tiny, bumpy, wrinkled limes, use kaffir lime leaves (easier to find year-round) cut into a very fine chiffonade and add them with the lemongrass and chilies.