Place the prickly pears and vodka in a pitcher, cover tightly with saran wrap and refrigerate for at least 2 days, and up to a week.
Strain the brightly colored infused vodka, using a spatula to press the pulp.
In a saucepan, combine the water and sugar and stir until completely dissolved (this makes a simple syrup). Cool, and add the simple syrup to the vodka.
Place in mason jars and screw on top tightly. Keeps for several months.