These Margaritas are my favorite because the pineapple juice cuts the sour of the lime and sweetens the drink perfectly. If there is any extra just freeze it, it doesn't freeze solid because of the liquor and it's ready for you whenever you want a margarita. Even better make up a few batches ahead of time and freeze.
Rub rim of cocktail glass with wedge of lime. Place salt (I like to mix salt and sugar) in saucer; spin rim of each glass in salt (Optional). Set prepared glasses aside. Combine limeade concentrate, tequila, and Triple Sec and pineapple juice in container of an electric blender. Add enough ice cubes to fill blender; blend well. Pour beverage into prepared glasses; garnish with a slice of lime, if desired.