Combine the salt, sugar, coconut, and lime zest on a shallow plate.
Dampen the rims of 2 margarita glasses with water, then dip each into the mixture to coat.
Chill the glasses until needed.
Pour the tequila, lime juice, and rum into a cocktail shaker, then add a large handful of ice.
Shake until the outside of the shaker feels ice cold.
Drop a few ice cubes into each of the prepared glasses.
Strain the cocktail evenly between each glass.
Enjoy, and please remember to drink responsibly.
2 servings