Combine sugar, orange rind and juice in a medium-size heavy saucepan; cook over medium heat, stirring constantly, until sugar dissolves. Cover and continue to cook over medium heat 2 to 3 minutes to wash down sugar crystals from sides of pan. Uncover and cook, without stirring, until mixture reaches soft ball stage (238°).
Pour orange mixture into a well-buttered 15- x 10- x 1-inch jellyroll pan. Let cool slightly. Knead, with buttered hands, until fondant is smooth and creamy. Shape fondant into 1/2- inch balls; place on waxed paper. Cool at least 1 hour or until firm.
Place chocolate in a stoneware bowl that has been placed over hot water. Stir until chocolate melts. Using 2 forks, quickly dip balls, one at a time, into melted chocolate. Place on waxed paper; cool until firm. Store in airtight containers.