Combine water, sugar, and hibiscus flowers in a large pot and bring to a simmer. Once it simmers, remove from heat and let steep for 20 minutes. Strain and add 1 tsp. of chile piquín. Let cool.

Pour hibiscus mixture into jumbo ice tray and freeze overnight.

Run a lime wedge around the edges of two whiskey (rocks) glasses, and dip them on the salt. Set aside.

In a cocktail shaker combine tequila, Cointreau, and lime juice. Fill the shaker with ice and shake until completely chilled.

Unmold 4 jumbo ice cubes, and place in the prepared glasses. Pour classic margarita over the hibiscus ice and serve.