This refreshing update on the classic gin and tonic is an easy sipper, thanks to summery cucumber slices and plenty of lime juice. You can use any gin you have on hand, but we’re partial to Hendrick’s, which has a slight cucumber flavor, for this cooler. A note on the cucumber slices: it may be tempting to nibble them out of your drink right away, but try to resist the urge. After several minutes’ contact with the lime juice, gin, and tonic water (about as long as it takes to finish the cocktail), they pickle ever so slightly, taking on a lovely crisp flavor.