Start the horseradish cream at least 30 minutes before serving to develop the flavors. Sprinkle the cucumber with ¼ teaspoon salt. Let stand for 10 minutes. Wrap in paper towels or a kitchen towel and squeeze out as much liquid as possible. In a small bowl, combine the cucumber with the other ingredients. Adjust the seasoning to taste. You can refrigerate the horseradish cream, but let it come to room temperature before serving.