Chill serving glasses by placing them in a freezer or filling them with ice cubes.

Add the gin and cucumber syrup to a cocktail shaker.

Fill the shaker with crushed ice, place the cap on the shaker, and shake it vigorously for 10 seconds.

Strain the mixture into a large mixing glass with cucumber slices.

Add the bitter lemon tonic and stir to combine. Distribute between the serving glasses and garnish each one with a cucumber slice, 3 pink peppercorns, and a pinch of the wild hibiscus salt.