Exercise in a wheelchair

These aren't apps but they still might provide some useful information. You could use a regular app and modify certain exercises as needed, once you know what the modifications are. Many people have to make modifications of one sort or another. Do you have rehab trainer or physical therapist who might have some resources?
https://www.nhs.uk/Livewell/Disability/Pages/fitness-for-wheelchair-users.aspx
https://wheelygoodfitness.com/
http://101mobility.com/blog/wheelchair-exercises/
http://disabilityhorizons.com/2016/10/top-10-exercises-disabled-people/