As I was a temp, I was referred through the hiring hall in Toronto, the Power Workers Union. For full time permanent employment I believe you apply online
A comparatively faster and effective way is through an employee referral. Security clearances do take a lot of time however. Expect to go through a 3-4 month recruiting process comprising of 3 interviews, residential/employment/criminal/educational/travel background checks, lots of paperwork and a CSIS approval.
Can take a while due to the security requirements
Through CSIS approval and long hiring process.