1. Combine first 3 ingredients in a saucepan; bring to a boil over medium-high heat. Cook for 2 minutes, stirring frequently. Remove from heat, and cool to room temperature.
2. Place sugar mixture in a blender or food processor. Add melon, juice, and salt. Process until smooth. Pour melon mixture into a 13 x 9–inch baking dish. Cover and freeze 8 hours or until firm. Scrape entire mixture with a fork until fluffy. Store in an airtight container in freezer.