Beet and Cucumber Salad with Creamy Horseradish Dressing

Name: Beet and Cucumber Salad with Creamy Horseradish Dressing
Yield: 4 Servings
Ingredients: 2 large beets, trimmed; 1/2 cup sour cream; 5 1/2 teaspoons Champagne vinegar or white wine vinegar; 2 teaspoons prepared white horseradish; 1 1/4 teaspoons sugar; 2 bunches watercress, tough stems trimmed; 2 tablespoons corn oil; 16 1/3-inch thick rounds unpeeled English hothouse cucumber