Recipe is adapted from a recipe in the excellent book of Japanese home style recipes, "Everyday Harumi." Really the main thing I changed was making it a bit more of a Szechuan flavor profile by adding some prickly ash oil and omitting the sesame oil.
There are two ways you could prepare the beans. I personally like to sous vide them, but you could also blanch them for a few minutes before sauteing.
Cut beans in half, or smaller if you prefer more bite-sized pieces
If blanching the beans, cook them in salted boiling water for 3 minutes, and then strain them and stop their cooking by placing them in a bath of ice water
If cooking the beans sous vide, cook them according to the timing and temperature in the sous vide green bean method. I actually like to also throw about half the soy sauce, ginger, garlic, leeks, and prickly ash oil into the bag and sous vide them all at once.
Add some neutral oil (I normally use avocado oil but any kind of oil is fine) to a skillet, and over medium heat, cook the garlic, ginger, and leek for a minute to infuse their flavors into the oil
Add the pork to the oil and stir fry until the meat is well browned on all sides
Add the green beans to the pan as well as the soy sauce and prickly ash oil and add as much of the pepper flake as you can stand
Saute everything in the skillet until the beans are warmed through and the beans have just started to blister a bit from the oil and heat
Serve with steamed white rice