• Muddle the mint leaves and tequila in a shaker. Top with several ice cubes and pour the grapefruit juice, lime juice and hibiscus simple syrup over the ice. Shake well.
• Rub a lime wedge along the edge of a glass. Combine the grapefruit zest and kosher salt on a small plate; rub the glass edge into the zest/salt combination. Fill the glass with ice.
• Strain the margarita into the glass and garnish with a lime wedge and a mint leaf.

To make the hibiscus simple syrup

• Bring water to a boil over medium-high heat in a small pot. Turn off heat, add the hibiscus flowers and steep for 5 minutes. Strain out the hibiscus flowers. Return the pot to the stove and add the sugar. Heat on medium until the sugar dissolves. Remove from heat and allow to cool before using.