How to Make It
Spread salt on a small plate. Rub lime wedge halfway around rim of a 10-ounce glass (such as a double old-fashioned). Dip moistened side of glass in salt to lightly coat. Set aside.
Place tequila, syrup, Persian lime juice, and Key lime juice in a cocktail shaker filled with ice. Cover with lid, and shake vigorously until chilled, about 30 seconds. Strain into prepared glass. Fill glass with ice.