Questions my facility asks include:
What rights do you think people with disabilities have? (you'd be surprised how many people do NOT think the answer is "the same as everyone else")
What would you do in [insert common situation here]? They'll insert various situations common to the particular facility and residents.
Are you familiar with [insert medical conditions specific to the residents here]? How much experience do you have?
Can you handle bodily fluids? [Sounds strange to ask a nurse, I know, but we've had a number of them who could *not* handle Depends and such, so this was added.)
Honestly, I would suspect it will be easy to get hired as there is high, high turnover in the DD field. It can be brutally hard in ways that they will not warn you about during orientation, but it is equally rewarding, and to me the rewards surpass the difficulty. Good luck!