Peel the cucumbers. Cut into thin slices and place in a large bowl. Sprinkle the cucumber with 1/2 teaspoon salt, 1/2 tablespoon vinegar and 1/4 teaspoon sugar. Gently toss. Let stand 30 minutes. Drain, gently pressing out liquid with the back of a spoon. Pat dry with paper towels.
Meanwhile, place the sour cream in a medium bowl and whisk until light. Whisk in the shallot, remaining 2 tablespoons vinegar, 3/4 teaspoon sugar, the celery seed, chives and salt to taste. Layer 1/3 of the cucumber slices in bottom of a small serving dish. Spoon 1/3 of sour cream mixture on top. Sprinkle 1/3 of dill. Continue to layer until all ingredients are used up. Sprinkle top with pepper to taste. Chill well. Serves 4.
