I don't agree with Brother Fighter in point 1 and 3...Unless u get her salary slip thru legal methods, its inadmissible. Getting a recruiter to call you and recording the conversation is also fruitless.
Point 2 I agree with. File CrPC 91 and ask the court to ask her to submit all her banking records. In the same CrPC 91 ask the court to direct the company to submit and affidavit about if she is working there are not and if she is, how much she is earning. Companies WILL HAVE TO comply, else it will be contempt of court. Remember, if they don't listen to trial/family court, appeal it in High court and then they have to listen.
Also, as a strategy, wait till your wife has come on the stand and, under oath, made a statement that she is not working. Once she has done this, and you file for CrPC 91, then ask the judge take up perjury charges against her.