Make the cheese mixture ahead of time for these appetizers. That way it's chilled and ready for assembly come party time.
In a small bowl stir together feta cheese, sour cream, parsley, dried tomatoes, garlic, and pepper. Cover and chill for 2 to 24 hours.
Using a sharp knife, trim the ends from cucumbers; discard ends. Bias-slice the cucumbers into 1/4-inch-thick slices. Spoon 1-1/2 teaspoons cheese mixture onto each cucumber slice. Arrange cucumber slices on a serving platter.
In a small bowl combine basil and olives. Spoon some of the mixture over each cucumber slice. Serve immediately. Makes 30 appetizers.