Peel oranges, reserving orange sections for another use. Scrape off and discard white portion of rind.
Bring orange rind, 2 cups water, and salt to a boil in a medium saucepan. Reduce heat; boil 30 minutes. Drain. Add enough water to cover rind, and boil 10 more minutes. Drain and cool. Scrape and discard any excess white portion from orange rind. Cut rind into 1/4-inch strips. Set aside.
Combine 2 cups sugar, 1 cup water, and corn syrup in a medium saucepan. Cook over medium heat, stirring constantly, until mixture reaches soft ball stage or candy thermometer registers 230°. Add rind, and cook 5 minutes or until rind is translucent; drain. Toss rind with sugar.
1 large grapefruit may be substituted.