Basically - the US considers any of certain acts regardless who commits them or where - illegal - and Canada has treaty obligation to detain & extradite individuals to the US who fulfil certain criteria (such as aiding and abetting the breaking of sanctions designed to limit the spread of weapons of mass destruction to 'rogue states.')
Being as the Canadians are still considering the legality of the extradition, that cannot reasonably answered. Canada certainly does have treaty obligation (and so the legal justification) to detain pursuant to investigation.
Legal & regulatory frameworks have a great many vulnerabilities and most of them become essentially unenforceable without some measure of jurisdictional cooperation. I don't know how it could come as a surprise that somebody committing a murder in one state or nation might still be considered guilty of that crime after moving to another jurisdiction, regardless of whether the act was considered criminal in the destination, the criteria for detention are different.
As everything upon which humans provide for themselves or others (or harm themselves or others) can be acquired with money, it follows that financial activities are of some importance.
Each Contracting Party agrees to extradite to the other, in the circumstances and subject to the conditions described in this Treaty, persons found in its territory who have been charged with, or convicted of, any of the offenses covered by Article 2 of this Treaty committed within the territory of the other, or outside thereof under the conditions specified in Article 3 (3) of this Treaty.
(1) Persons shall be delivered up according to the provisions of this Treaty for any of the offenses listed in the Schedule annexed to this Treaty, which is an integral part of this Treaty, provided these offenses are punishable by the laws of both >Contracting Parties by a term of imprisonment exceeding one year.
The Schedule is fairly irrelevant to the question, the articles demonstrate that the law/treaty obligation applies to the crime committed/charge proposed, the country of origin of the individual in question is irrelevant unless Canada also happens to have another treaty ratified/legal within it's legislature that denies such an extradition
base on country of origin.
- What activities by foreign financial institutions can subject them to CISADA sanctions?
As described in the Iranian Financial Sanctions Regulations, the sanctionable activities of a foreign financial institution are:
Facilitating the efforts of the Government of Iran (GOI) to acquire or develop Weapons of Mass Destruction (WMD) or delivery systems for WMD or to provide support for terrorist organizations or acts of international terrorism;
Facilitating the activities of a person subject to financial sanctions pursuant to UNSCRs 1737, 1747, 1803, or 1929, or any other Security Council resolution that imposes sanctions with respect to Iran;
Engaging in money laundering, or facilitating efforts by the Central Bank of Iran or any other Iranian financial institution, to carry out either of the facilitating activities described above; or
Facilitating a significant transaction or transactions or providing significant financial services for: (i) the Islamic Revolutionary Guard Corps or any of its agents or affiliates whose property and interests in property are blocked pursuant to the International Emergency Economic Powers Act (IEEPA), or (ii) a financial institution whose property and interests in property are blocked pursuant to IEEPA in connection with Iran’s proliferation of WMD, Iran’s proliferation of delivery systems for WMD, or Iran’s support for international terrorism.
That there are political factors involved does not mean it is justified to say that something is politically motivated, though every law is a result of political motion.
In this case we might say it is, one might imagine the US Federal government feels it needs to attract public and international attention to the reality of Chinese espionage as a significant proportion of the American public has apparently arrived at the view that everybody in the world is fluffy except the Feds and the Russians.