In my more than a decade of experience I have worked on either side of the table. From being a consultant to hiring a consultant to running my own business consulting company. I believe you should think more about the things that you should ask the consultant than questions a consultant may ask to assess your business.

Whatever question a consultant may ask shouldn't bother you as he/she will ask only about your business and nothing personal. But, what you should ask a consultant is going to define the value of the engagement. Hence, make sure you are clear with:

1. What problem do you expect the consultant should help you solve?
2. What are the diverse capability required to solve the problem and whether the consultant possess them all?
3. How would you measure the success of engagement? Don't try to quantify the success. Sometimes qualitative aspect outweighs the quantitative stuffs.
4. Time frame of the engagement
5. Engagement model and approach
6. et al

I hope above could be of some help. Is there anything specific you're looking at? Feel free to reach out with more clarity to receive clarity. I am just a buzz away and our capability spans across business, management, and technology.