Security Briefings, Tax Returns, and Freedom of Information

As an American citizen, do I have a right to know about the financial dealings (tax returns) of a candidate who is currently receiving top secret security briefings that could be used to aid and abet enemies of the United States who might harm my family?

I am not comfortable with him getting security briefings when already we know Manafort has financial ties to Russia, as well as business ties (ex. his son admitted a large portion of their business was with Russia). Why can't the Freedom of Information Act be used here? Why can't an injunction be filed until the tax returns are released?