It's quite difficult since many / most employers are not willing to go through the LMIA process. There's also no easy way to find employers who are willing to go through the process.
If you plan to try, make sure you have enough money saved to live in these cities for at least six months withouit working and without having coverage for any social services, including health care. And check out rental prices in advance. They are very high. For example, single rooms in shared accommodations in Toronto are going for over $1,000 per month right now. Vacancies are also extremely low. This applies to both cities.