Heat the oil in a wok or skillet. Add the garlic and ginger, and stir-fry the ingredients for 30 seconds.
Add the green beans, and stir-fry them over high heat for 2 to 4 minutes.
Add the sesame oil and salt (if desired), toss the ingredients to coat them, and serve the beans.
Preparation tip: The beans are supposed to be tender-crisp and shriveled or even charred a bit on the outside. If you like tenderer beans, cover the pan after adding the sesame oil and salt, and continue cooking the beans for a few minutes over moderately low heat.