Using a lime wedge for each glass, moisten the rims of 24 serving glasses and dip them in coarse salt. Set aside.
In a large, high-powered blender, combine the pears, margarita mix, lime juice, sugar, and crushed ice until smooth. Divide between the prepared glasses, garnish with a pear slice and lime wedge, and serve immediately.
Add 1-1/2 ounces tequila to make an adult beverage.