In a medium saucepan stir together sugar and gelatin. Stir in 1/2 cup of the cranberry juice. Cook and stir over medium heat until sugar and gelatin dissolve. Remove saucepan from heat. Stir in the remaining 2 cups cranberry juice and carbonated water.
Transfer gelatin mixture to a large bowl; cover and chill for 1 to 2 hours or until slightly thickened. Stir in pears and dried cranberries. Divide gelatin mixture between ten to twelve 5- to 6-ounce individual molds or custard cups. (Or, pour gelatin mixture into a 2-quart baking dish.) Cover and chill for 4 to 24 hours or until firm.
Remove gelatin from molds, if using. If desired, garnish each salad with sugared cranberries.