Actually, if the interviewer/s starts asking 'do you have any questions?', it means he's giving you the green light to ask as many questions about the job/company as possible. If it were me, i would ask about the company itself, more about the job, what i can expect from the company/job, the benefits, and any other questions related to the job. You may ask about the salary, but it is not encouraged, because it will look as if that's the only thing you ever cared about. Sometimes, from your questions, you will get more points/marks if you ask the right ones.
Sometimes also, the interviewer will ask you tricky questions. Eg. he will ask you a question that if you're not cautious, you will criticize other companies when you answer. So this is very important. No matter what your aswer is, NEVER ever talk bad about the other companies/the ones you have worked for. You will automatically be rejected if you do this. If you must say that your opinion is different than the company you are talking about, then you must state that eventhough you have a different opinion, but you respect the decision taken by that company.
A lot of people criticize/talk bad about their previous employers, not realizing that ANY potential employer would not want to hire a person with this attitude. If you can talk bad things about your previous employer, what happens if the future employer employs you, and then you quit after some time? Would you be talking bad things about them too?
Be firm and look them straight in the eye. Smile and wait for them to question you, before you start a conversation. Act as if the job already belong to you. Don't try to suck-up to anyone/bodek, just be yourself and don't show that you are desperate. Be firm, but available. All the best.
P.S It's good to find out about the company's background before you go for the interview.
Psstttt... what ID? 
