Toast the sesame seeds in a dry skillet over medium heat, tossing frequently, until golden, about 4 minutes. Cook the beans in 2 inches of boiling salted water for 2 to 3 minutes. Drain well.
Heat the vegetable oil in a large nonstick skillet until the oil shimmers and smokes. Add the beans and stir-fry for 5 minutes, until they begin to caramelize and brown at the edges. Add the crushed red pepper, sesame oil, coarse salt and toasted sesame seeds. Toss a minute more. Remove from the heat and serve.