3 medium cucumbers, peeled (can be made with skins on!)
1 cup yogurt
2 Tbsp lemon juice
3 scallions or garlic tops, thinly sliced
1 Tbsp fresh minced dill
1/2 cup cold water
Slice 2 cucumbers and puree them in a blender with yogurt and lemon juice.
Blend until smooth.
Pour mixture into a bowl and add scallions, dill, and water.
Grate remaining cucumber and add to soup.
Chill at least 1 hour before serving.