Empty frozen limeade into blender. Fill blender about 2/3 full with ice (cubes or large chunks). Fill empty 6 oz. limeade can with liquid margarita mix; pour over ice in blender. Fill can 1/2 full with tequila; pour over ice. Fill can 1/2 full with triple sec; pour over ice. Blend on high speed until mixture is of "daiquiri" consistency. Add more ice to desired consistency. Serve in glasses with salted rim and garnish glasses with split lime slices.
To salt glass rims, rub a lime slice around the rim, turn glass upside down into margarita salt and twist glass.
