Step 1

Salt the rim of 2 cocktail glasses by rubbing a grapefruit or lime wedge around each edge and dipping them into a small plate of salt. Fill each glass halfway with ice.

Step 2

In a cocktail shaker, combine the tequila, grapefruit juice and lime juice with some ice. Shake for 30 seconds and then fill each glasses with equal amounts of the mixture. Top with the sparkling water and garnish with grapefruit wedge.