Make the simple syrup: Combine the sugar and 1 cup water in a small saucepan. Cook over medium heat, stirring, until the sugar dissolves, about 2 minutes. Transfer to a medium bowl and refrigerate until chilled, about 1 hour.
Combine the blood orange juice, cherry juice, lemon juice, chilled simple syrup and 2 cups cold water in a pitcher. Refrigerate until chilled, at least 30 minutes.
Just before serving, stir the tequila into the punch, if using. Decorate the rim of the pitcher with red gel icing, allowing some to drip down the side. Serve over ice.
Photograph by Ralph Smith