To prepare pickled watermelon rind: Trim off skin, and cut rind into 1-inch cubes. Sprinkle pickling salt over rinds and refrigerate overnight.
The next day, rinse the rind, and drain well. Cover rind with cold water in a large saucepan. Cook on medium heat just until tender.
In another pan, heat sugar and vinegar to a boil. Tie mustard seeds, cinnamon and clove in a cheesecloth. Place in the sugar-vinegar mixture to infuse it. Add watermelon rinds, and simmer about 35 to 50 minutes until rind is transparent. Remove spice bag, and let rinds cool in the mixture.
To prepare melon shots: Peel and slice Galia melons. Place melon in a blender with mint leaves and lime juice. Blend until smooth. Pour mixture through a coffee filter or sieve. Refrigerate until serving.
To prepare the salad: Using a small melon ball scoop, make melon balls from the Charentais melons. With a small cylindrical cookie cutter, cut small cylinders from the watermelon. Alternatively, you can use a melon ball scoop to make small balls instead.
In a bowl, mix melon balls and cylinders with orange juice, as well as orange and lime zests, to taste.
In another bowl, toss tomatoes with basil, mint, olive oil, balsamic syrup, sea salt, and pepper.
To serve: Mix together melon balls and tomato salad. Place in the center of a serving plate. Arrange pickled watermelon rinds around the melon-salad mixture. Pour chilled melon juice into shot glasses or martini glasses. Serve.