Peel and chop the cucumbers. If they have large seeds, scoop them out with a spoon. This keeps the soup smooth and less watery.
In a high-speed blender or food processor, combine chopped cucumbers, Greek yogurt, garlic, lemon juice, dill, za’atar, salt, and pepper. Blend until completely smooth.
Add cold water 1 tablespoon at a time and blend again until you reach your desired consistency. It should be creamy but still pourable.
Transfer the soup to a bowl or container and refrigerate for at least 2 hours to allow the flavors to develop. The longer it chills, the better it tastes.
Stir the soup before serving. Pour into bowls and garnish with a drizzle of olive oil, extra dill, and (if desired) toasted pine nuts or feta crumbles.