Place cucumbers in a large bowl. Whisk yogurt in a separate bowl using a fork until yogurt is smooth and liquefied; pour over cucumbers. Add dill, garlic, oil, and salt to cucumber mixture; toss to coat. Stir in enough water to reach desired consistency. Refrigerate until chilled, at least 30 minutes.
Ladle soup into serving bowls; add about 2 ice cubes to each bowl.