Boil (a rolling boil) the beans for five minutes.
While the beans are boiling make a dressing (roughly for a pound of beans):
two tbs coarse mustard
two tbs vinegar (I used red wine, but white or rice would work, maybe balsamic)
six tbs olive oil
one clove grated garlic
one small minced shallot
Drain the beans and dress while hot.
We ate every bean that could be reasonable picked with this recipe this weekend.