Place salt on a plate. Run the edge of a lime slice around the outside rim of a margarita (or cocktail) glass. Roll the outer edge of the rim in the salt until coated. Repeat on four cocktail glasses. Set aside.
Combine all ingredients in a blender. Blend on the highest setting until completely smooth. If necessary, scrape down the sides with a rubber spatula. Garnish with a lime wheel. Serve immediately.