1. Fill a cocktail shaker with ice. Pour in the tequila, Cointreau, blue curaçao, and sweet and sour. Shake vigorously for 30 seconds.
2. Place margarita salt on a small plate in a thick layer. Cut a slit in the center of the lime wedge and then place it on the rim of your glass. Run the lime wedge around the entire glass to get the rim wet.