In a blender in batches, puree the tomato, watermelon, cucumber, bell pepper, fennel, onion, olive oil, vinegar, and enough ice water to achieve a soup like consistency (about 1 cup). Season with salt and add more vinegar if necessary. Chill thoroughly.
Divide the soup among 8 cold bowls. Garnish each serving with a spoonful of diced watermelon. Drizzle with extra virgin olive oil and serve.
Enjoy with Cakebread Cellars Vin de Porche.