Moisten the outer rim of a highball glass with a lime wedge and coat lightly with salt. Fill the glass with ice. Fill a cocktail shaker with ice, then add the tequila, grapefruit and lime juices and simple syrup; shake well. Strain into the glass. Gently stir in the Virgil’s grapefruit soda and garnish with a lime and grapefruit wedges!
