Bring tamarind, sugar and 3 cups water to a boil in a 2-quart saucepan. Cook, whisking constantly, until sugar and tamarind dissolve, about 3 minutes. Transfer tamarind mixture to a bowl and refrigerate until chilled. Whisk in the chile powder and pour into six 3-ounce ice-pop molds. Transfer molds to the freezer and freeze until slushy, about 1 hour. Insert a popsicle stick into each mold and freeze until pops are solid, about 3 hours more. To release ice-pops from molds, run the bottom of the molds briefly under warm water.