Remove the skin from the prickly pears and chop roughly.

Add chopped prickly pears to a food processor or blender with tequila blanco, Cointreau, lime juice and sugar. Puree until smooth, then strain the puree to remove the prickly pear seeds.

In a clean blender or food processor cup, add the strained puree and 3 cups of ice and blend until the mixture becomes slushy.

Wet the rims of the glasses by rubbing with a lime wedge. Put the Tajín in a flat dish and dip the glass rims in it until they’re coated all the way around. 

Pour the margarita into the glasses and serve immediately.