Bring a large pot of salted water to a boil. Add the green beans and cook until just barely tender, about 5 minutes. Drain well (they will continue to soften a bit as they cool, so drain them just before they are done to your liking).
While the beans are cooking, in a large serving bowl, whisk together the honey, Dijon mustard, vinegar, olive oil, ½ teaspoon salt, and pepper.
Toss the green beans in dressing, taste and adjust seasonings as needed, and serve warm or at room temperature.