I feel very uncomfortable during this period, I don't know what to do, should I speak something then or ask about project?
The way I see it, is they are the interviewer, and the ball is in
their court. It is not your responsibility to strike up conversation just for the sake of filling in the silence. Let them drive until they turn it over to you.
As far as what questions to ask...
You: Of all the employees you've personally recommended for hire, if you were to look at the top 10%, what are the qualities/skills they exhibit which make them successful at [
company name]?
Depending on how the interviewer responds, you may be able to potray some personal initiative and confidence by letting her know that the next time someone asks her to think about the top 10% of employees she's hired...you want to be on that list.
This worked rather well for me.
Good luck.