Nearly always, at the end of your interview, the interviewer will ask if you have any questions.
You should always have one or two prepared in advance as having no questions at all makes you appear rather passive and uninterested. You want to appear bright and enthusiastic, let your questions project that image.
It is probably not a good idea to ask about the salary or benefits at this stage – remember, you are motivated by the higher ideals of ‘opportunity’, ‘challenge’ and ‘increased responsibility’! First, you have to demonstrate that you can do the job, that you want the job and that you will fit in. When you receive an offer, you will have a chance to discuss salary details at that stage.