Cut a watermelon into big disks, about one inch thick.
Using a small round cookie cutter (bearing in mind that this makes a mouthful even with small diameter circles), cut out little cylinders of watermelon, avoiding the seedy spots. Seedless watermelons are not exactly seedless.
Cut each little cylinder into 3 or 4 disks. Set the watermelon disks onto paper towels briefly to drain excess juice.
Cut the log of goat cheese into disks of approximately the same thickness as the watermelon disks.
Use the cookie cutter to trim the cheese to the same size as the watermelon, taking care not to let the goat cheese crumble too much.
Place a disk of goat cheese onto each disk of watermelon. Top each with a piece of bacon and a basil leaf.
At the last moment, drizzle each bite with a little balsamic vinegar.