1. Trim and discard cucumber ends. Cut cucumbers in half lengthwise and thinly slice. In a bowl, mix cucumbers with 1 teaspoon salt; cover and chill at least 30 minutes or up to 4 hours. Drain well and pat dry.
2. Separate egg yolks and whites. Cut whites into slivers. Add to cucumber.
3. In a blender or food processor, combine yolks, sour cream, vinegar, mustard, sugar, and pepper; whirl until smooth.
4. To serve, mix sour cream dressing and dill with cucumbers. Add salt to taste. Line a wide bowl with lettuce leaves and spoon cucumber salad onto leaves.