Using lime wedges, moisten the rims of four margarita or cocktail glasses. Set aside limes for garnish. Sprinkle coarse sugar on a plate; hold each glass upside down and dip rim into sugar. Set aside. Discard remaining sugar on plate.
In a blender, combine the lemonade concentrate and raspberries; cover and process until blended. Press mixture through a fine sieve; discard seeds. Return raspberry mixture to blender; add the ice, strawberries, blueberries, sugar and tequila if desired. Cover and process until smooth.
Pour into prepared glasses. Garnish with reserved limes.
Test Kitchen Tips
Tequila comes in two main types: gold (amber-colored) and silver (clear). Gold tequila may be aged or have caramel coloring or flavoring added to mimic the aging process. Silver tequila tastes more crisp and bright, and you may prefer it in this salad.
For a tasty virgin drink even the kiddos will love, leave out the tequila.