To salt the rim of the glass, add a good amount of salt to a shallow dish. Cut off a slice of lime and rub it around the edge of the glass. Dip the glass into the salt to coat the rim.

 In a large glass or cocktail shaker add the Mezcal, lime juice, orange juice, Grand Marnier, and simple syrup. Stir to combine or add ice to the cocktail shaker and shake until combined and chilled.

 Fill your serving glass with ice and strain your cocktail over the ice. Garnish with lime wheels or a lime wedge.