Purée 3 cups watermelon and transfer to a large, nonmetallic bowl. Add lime zest, lime juice, salt, garlic, tomato, cucumber, green pepper, red onion, vinegar, oil, and fresh herbs of choice. Add sugar and mix well by hand.
Chill before serving (at least 1 hour).
For a festive arrangement, fill martini glasses with the gazpacho, then add cubed watermelon, pineapple and raspberries. Garnish with mint leaves.