In a medium saucepan, cover the watermelon rind with water. Add coarse salt and boil. Cook the rind pieces for 5 to 7 minutes until tender. Drain and set aside.

In another saucepan, mix 1 1/2 cups white vinegar, 1 1/2 cups water, granulated sugar, cinnamon sticks, ginger slice, whole cloves, and black peppercorns. Bring to a boil while stirring until the sugar dissolves.

Pack the hot, drained rind into sterilized jars, then ladle the hot syrup over the rind, leaving about 1/2-inch headspace. Wipe the rims, seal with lids, and let cool to room temperature before refrigerating for at least 24 hours.