1 cup ice cubes
1 1/2 fluid ounces light rum
1 fluid ounce lime juice
1 fluid ounce triple sec
1 teaspoon white sugar
1 lime wedge (optional)
2 tablespoons white sugar, or as needed (optional)
Blend ice, rum, lime juice, triple sec, and 1 teaspoon sugar in a blender on the highest setting until smooth, 15 to 20 seconds. Pour into glass.
Spread 2 tablespoons sugar in a thin layer onto a small plate. Rub lime wedge around the rim of a glass. Dip glass rim in sugar to coat. Pour blended beverage into the prepared glass to serve.