Here you can see something I use almost everyday to peel, chop and slice vegetables one handed. I got this from the hospital 10 years ago, lots of trial and error but still works well enough.q
Here's how it works:
I always lay the peeler device thing on to a damp cloth first - this keeps it firm and stops it slipping.
Impale object on to triangular spikes
Using peeler or knife to peel or slice, flipping your veg over and spiking again to peel the under side. I find it easiest using a knife. It works for most veg, but long and thin roots such as carrots and parsnips I usually cut in half first.