Make a salted rim on a highball glass. Fill the glass with ice cubes. Add all ingredients. Garnish with a grapefruit wedge. The salt rim is quite easy to make. Take a wedge of lime or lemon, and wet the rim of the glass with it. Pour some coarse sea salt on a small plate and simply dip the glass rim in it. Voilà -- you just gave a glass the characteristic, cool Salty Dog look.