Mix 1/2 cup honey with 1/2 cup hot water and stir until honey dissolves. Let it cool. (It can be stored in the refrigerator and used to sweeten iced tea or coffee.)
In a lidded jar or cocktail shaker, add the honey syrup, the citrus juices, gin, and salt. Shake well and strain the drink into an ice-filled wine glass. Top it with a splash of tonic water and garnish with orange and lemon zest.