Wheelchair user weight loss?

I have gotten a bit 'chubby' recently and want to do something about it. I am confined to a wheelchair because of a neuro muscular disorder I was born with, so I am limited in what I can do for exercise. I have no mobility in my legs and good (but less than the average person) upper-body strength. Staying a healthy weight is important to me, so I can have what little independance I can. What can I do at home to lose some weight? I am dieting, I just want to know if there are some exercise I could do at home. Please, no trolling.