Hmm, you probably already thought about this...polishing her nails in her favorite color?
I agree that she needs to learn a more productive activity to help her release stress. ADHD means she needs to move. I allow my students to pace, walk or stand in classroom while listening to instruction. Frequent breaks during a predetermined and agreed time of focused work is rewarded with a quick (5 min) walk/run/skip outside with our para. I allow students to chose outside activities with a para such as bouncing a ball, spinning in circles or jumping at regular intervals (example every 20 mins for 3 mins). To make it fun I tell them with a wink that they "HAVE" to take it whether they need it or not.

It seems to help reduce the destructive behavior if they know an opportunity for whole body movement is given at regular frequent intervals. The stress is addressed before it builds and they seem to enjoy "HAVING" to get out and move. Hope that helps.