If desired, first rim glass with salt or sugar. Run a lime wedge around the rim of the glass, turning glass upside down into a plate of margarita salt or other coarse salt.
Fill glass with crushed ice, then add hibiscus syrup, lime juice, tequila and grand marnier, stir to combine. If desired, garnish with a wedge of lime, hibiscus flower (rehydrated or from a syrup) and or other fresh seasonal berries.
Make a batch using the same ratios and pour a scant half cup over ice.As a great non-alcoholic thirst quencher, stir one or two tablespoons of hibiscus syrup into a glass with ice and cold sparkling water.For an Agua de Jamaica dilute the hibiscus syrup with even more water and fill with ice.