Remove rind from watermelon, leaving a small amount of red flesh attached to rind. Reserve watermelon flesh for another use. Peel rind, and cut into 1-inch cubes (about 5 cups cubed). Place in a large bowl.
Stir together salt and 3 cups water. Pour over rind. Cover and chill 24 hours. Drain; rinse well.
Combine rind, sugar, next 2 ingredients, and 3/4 cup water in a large Dutch oven. Bring to a boil; remove from heat. Cool completely (about 1 hour), stirring occasionally. Cover and chill 24 hours before serving. Store in refrigerator up to 1 week.