Place chocolate chips in top of double boiler over barely simmering water over medium heat. Stir until melted. Stir in rice syrup and vanilla extract until blended.
In cup, dissolve kudzu in apple juice; stir into chocolate mixture. Cook, stirring constantly, until creamy and cloudiness has disappeared, 2 to 3 minutes. If icing is too thick to spread easily, stir in a little more apple juice. Use immediately.