Bring the water to a boil in a saucepan; add the beans, cover and reduce the heat. Cook 3-5 minutes; the beans should still be bright green and just tender, but not soft. Drain well and turn into a serving bowl. Add the dill and mix. In a saucepan, combine the remaining ingredients through the sugar and bring to a boil over high heat. Simmer for two minutes, then pour the hot dressing over the beans and mix well. Add the oil if desired. Let the beans stand for 10-20 minutes to allow the flavors to meld.