Boil salted water. Cook beans for 2-3 mins. Ice bath to preserve color and crispness. Drain and set aside.
Heat oil, add garlic, ginger, and red pepper flakes. Stir-fry for 1 min until fragrant.
Toss blanched beans in skillet. Stir-fry 2-3 mins until heated through but still crisp.
Whisk sauce, vinegar, and honey. Pour over beans. Cook 1-2 mins until sauce thickens.
Taste, season with salt if needed. Transfer to serving dish. Garnish with sesame seeds or green onions.