You don't, you find a US company with a local entity that hires you on a local contract in that country. That way you're compliant with taxes, and the company is compliant with employment law in your country.

The alternative to that is starting a sole-trader company in the country you're in, and contracting directly with the US company through it (or a remote-employees-as-a-service company that basically does this on the company's behalf for a fat fee).

I imagine it's a very crowded and competitive market to work remotely for US companies (and not through a sweat shop agency). The fact that a candidate has emigrated from US shouldn't typically be a big factor.

Go on Linkedin and search for small companies with less than 50 employees that have been in business for 3-5 years minimum. Figure out what they do, what they sell and if you would be interested in their company. Don't worry about whether they have a job listing or not.

Approach their founder(s) directly and sell yourself.