There was a time when the words lime sour didn't first bring to mind a cocktail mixer. It's tart, refreshing, ice cold, and the recipe for this lime sour couldn't be more simple. Some people like to shake a little salt over the top. You can see why. Somehow that salt makes the drink even more thirst-quenching — like an old-school Gatorade.
Pour the limes over an ice-filled glass and and top with soda water. Sprinkle salt over the top. Drink.