Pour into fine-mesh sieve set over a large bowl and let stand for 20 minute or until juice has drained through, stirring once or twice. DO NOT press puree or syrup will become cloudy. There should be about 2 Cups of watermelon juice. Discard the pulp.
Stir sugar into watermelon juice until dissolved.
Stir in grenadine, lime juice and salt.
Pour 1/2 Cup watermelon syrup and 1/2 Cup sparkling water into glasses and top with ice.