Sanctions governing trade with Iran have been codified through multiple acts of Congress and are overseen under the Departments of Treasury, Commerce, and State

Sanctions governing trade with Iran have been codified through multiple acts of Congress and are overseen under the Departments of Treasury, Commerce, and State, under Title 31 statute, with additional regulatory aspects within Titles 15 and 22. The statute (31 CFR 560.205) makes reexportation of US goods from a third party country by a non-US person explicitly illegal under US law. To the second aspect of your question, Canada is under treaty obligation to cooperate with extradition requests issued by US courts for fugitive apprehension, and Canadian courts will rule on whether the extradition is consistent with Canadian law before transferring the suspect to US federal custody. Welcome to the rule of law.