Using a large drill bit, drill a hole in the top of the watermelon that is deep enough to go through the rind.
Turn the bottle of vodka upside down and insert into the watermelon.
Once all the vodka has been absorbed into the watermelon remove the bottle and cover the hole with a piece of duct tape.
Roll the watermelon once or twice daily to evenly mix the vodka.
To serve slice melon and sprinkle slices with Kosher salt to taste