Slice the cucumbers and place them in a large bowl. season with 1 teaspoon of salt and toss. Let stand for 1 hour.
Meanwhile: in a small saucepan, combine vinegar, water and sugar. Heat over medium heat, until sugar dissolved, about 4-5 minutes. Remove from heat and allow to cool slightly.
Drain the liquids from the cucumbers. Add sliced onion and pour the dressing over the salad. Add chopped dill and toss until combined.