When I play with one hand I put my fingers this way:
Thumb - right CTRL
Index - Left arrow
Middle - Up arrow
Ring - Right arrow
Pinkie - It just stays there and look pretty.
I don't know what kind of disability you have, but if it is to your fingers, you may press left CTRL or space with your fist or even with the base of your palm. Good luck
.Due to my disability, my (legs and) left hand are weak, but my right hand (and fingers) are barely affected. (So, I can use my fingers the way you said you play with one hand.)
Also, until now, I didn't know CTRL places bombs.

(I've been using the spacebar.)