Steam green beans covered in 1/2-inch boiling water for 2 minutes. Transfer beans to a colander and run under cold water. Drain well.
Heat a wok shaped skillet or large nonstick frying pan over high heat. Go once-around-the-pan with wok or vegetable oil, add several drops sesame oil, and crushed pepper flakes. The pan will smoke. Add beans and stir-fry for 2 minutes. Add sesame seeds and coarse salt and toss to coat beans evenly.