In small saucepan, combine 2/3 cup sugar and water. Bring to a boil, stirring until sugar is dissolved. Cool 30 minutes. Refrigerate 30 minutes or until chilled.
In blender container or food processor bowl with metal blade, puree bananas. Add orange juice, lemon juice and sugar-water mixture; blend until smooth. Pour into ungreased 9-inch square pan; cover with foil. Freeze 4 to 6 hours or until firm, stirring several times.*
To prepare sauce, in blender container or food processor bowl with metal blade, puree 1 kiwi fruit and 2 teaspoons sugar. Serve over sorbet. Garnish with kiwi fruit slices.