Beyond enforcement of multilateral sanctions (especially the NK ones), the US and Canada (and the UK) could make it much more difficult for the elites to move assets out of China. Ban anonymous ownership of property, and start enforcing Chinese currency-control laws on government-connected individuals. Sure, President Xi might be able to evade Chinese law in China, but good luck convincing the Southern District of New York to look the other way.
Any ethical concerns aside, why would we break our own laws when enforcing them (and China's as written) is much more effective?
Beijing doesn’t care about the average Chinese. But its elites? It cares as much as any other government.
Aside from the fact that it's morally reprehensible...
For example, we should be subjecting Americans to the TSA bullshit that they dole on others.