In a small saucepan, combine the hibiscus flowers, water, and sugar. Bring to a boil, then reduce heat and simmer for 10 minutes. Strain the mixture, discard the flowers, and let the hibiscus syrup cool.
In a large pitcher, mix the cooled hibiscus syrup, lime juice, tequila, and triple sec. Stir well.
To serve, rim the glasses with salt by rubbing a lime wedge around the edge and dipping it into salt. Fill the glasses with ice and pour the margarita mixture over the top. Garnish with lime wedges.
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