I think the traditional method for it is to fry Fry them, but usually I blanch them in water first and then rinse under cold water and set aside. I usually just make a sauce out of some rice wine vinegar, a tsp of sugar, a shot of soy sauce and a bit of sesame oil. I fry a bit of fresh ginger in some sesame oil, add some garlic chili paste, and then add the beans and the sauce and fry till warmed through. You can omit the blanching and just follow a recipe like
this one though. Probably one of my favorite chinese dishes that I often use as a side for many meals.