Slice 2 of the cucumbers, and place them in a large bowl. Then take 4 of the limes and peel off the rind. Add the rind to the bowl with the sliced cucumbers. Next squeeze the juice from the limes.Pour the gin over the cucumber and lime. Then take a wooden spoon and muddle the mixture crushing the cucumbers and lime rind for about 3 minutes. Place in the fridge to chill for at least 2 hours.When you are ready to assemble the cocktails, strain the gin to remove the cucumber and lime rind.Mix the cucumber and lime infused gin with the tonic water. Slice the remaining cucumber and lime and use the slices as garnish.Serve the cucumber lime gin and tonics over ice.