Rub a lime wedge along the rim of the glass, dip in tequila salt, and set aside.
Make the mango puree:
Add the mango and water inside a blender and blend until smooth.
Make the cocktail:
Pour the mango puree into your cocktail shaker. Add Mezcal, lime juice, and cocktail syrup (if using). Shake vigorously until all the sides are frosted.
Serve:
Fill a glass with ice and strain the mango margarita over the ice.