Beet and Tomato Gazpacho

Name: Beet and Tomato Gazpacho
Ingredients: 2 slices red or white onion; 1 large beet (about 6 ounces), roasted; 1 small (6 ounces) cucumber or 1/2 long European cucumber peeled and coarsely chopped; 2 pounds ripe tomatoes, quartered; 2 sticks celery, coarsely chopped; 2 large garlic cloves, halved, green germs removed; 2 tablespoons sherry vinegar, plus a little extra for the onion; 3 tablespoons extra virgin olive oil; Salt to taste; 1/2 to 1 cup ice water; 1/2 cup diced cucumber; Slivered fresh mint leaves