For the Hibiscus simple syrup, mix the sugar, hibiscus flowers and water in 2-quart saucepan. Bring to a boil over medium-high heat; stir until the sugar is dissolved. Remove from heat; let stand 30 minutes. Strain mixture. Cover and refrigerate. Makes 1 1/3 cups. To make the margarita, add 1 ounce of the simple syrup, the tequila, the orange liqueur, and the lime juice to a cocktail shaker. Fill shaker with ice; cover and shake vigorously. Strain into cocktail glass filled with fresh ice and salted rim. Garnish with lime slices.