In a 6-quart pan over high heat, bring 3 quarts water to a boil. Add beans and cook until tender-crisp to bite, 3 to 5 minutes. Drain, immerse in ice water until cool, and drain again.
In a serving bowl, mix vinegar, sesame oil, soy sauce to taste, ginger, sesame seeds, garlic, and honey. Add green beans, onion, and bean sprouts and stir gently to coat. Serve at room temperature, or chill airtight up to 3 hours, and serve cold.