Make tequila syrup: Combine all syrup ingredients. Place on medium heat until sugar dissolves. Chill until cold.
Make triple sec whipped cream garnish: Combine whipped cream ingredients and beat to stiff peaks. Pipe rosettes on waxed paper-lined pan. Freeze.
Make soup: In a food processor place 3 cups of watermelon. Pour out excess juice and reserve. Puree watermelon until smooth. In a bowl combine the melon puree, the reserved juice, 1 1/2 cups tequila syrup, 1/4 cup tequila, juice of two limes and chill. In another small bowl combine 4 tablespoons diced melons for garnish, 1 tablespoon triple sec, and lime zest and chill. To serve, place whipped cream garnish in the bottom of a Kosher salt-rimmed bowl or glass. Pour 6 ounces of soup into the bowl or glass. Garnish with 1 tablespoon of the diced melons and sprinkle with salt.