When your spouse fills out her DS-160 form, she will be asked to disclose her marital status. She will also be asked to identify people who are traveling with her and her relationship to them. Even later in the form she will be asked to identify her spouse, spouse's nationality, and spouse's nation of residence. She will thus need to indicate that she is married and identify you as her spouse.

It would thus make no sense to try to conceal the relationship -- something that would require your wife's making false claims on her visa application, and could cause her to be barred from entering the United States -- as opposed to simply explaining that she wishes to enter as a tourist for a couple of weeks before returning home to Iran.