How to Make It
Rub the rim of two rocks or margarita glasses with a lime wedge. Swirl the rims through a small pile of kosher or sea salt to salt them. Add ice cubes to the glasses.
In a cocktail shaker muddle the blueberries and lime juice until the blueberries are pulverized. Add the tequila, Simple Syrup, bitters and a handful of ice to the shaker. Add a left over rind or two from the limes. Shake vigorously for 15 seconds, and then strain into the salted glasses.