If this person asks you what your salary requirements are, they are probably trying to do one of two things. They are either trying to screen you, or they are trying to determine whether to recommend you for a second interview. Do not give a dollar figure if at all possible. If they pressure you, give them a range. In an interview, use the word compensation instead of salary.
Compensation is all-inclusive of benefits, commissions, incentives, vacation time, bonuses, etc.
Salary is limited to just salary. Don't give a potential employer the impression that you will settle for just salary when other elements of compensation, including perks, may matter to you. An employer will not offer you more money simply because you ask for it, even if you really, really, really need it to make your mortgage payment. Talk about what you can do for the company and why that merits the compensation you are requesting. It is absolutely essential before you negotiate for the employer to realize your value.