The legal status of this activity is lighter in CA than the USA so that makes things much simpler. Screening, at least with the agencies, is mostly call and let them know your hotel, name and room so they can call you back. With some of the (IMO) lower end C-agencies not even that.

 
http://rentry.co/kgirls has a good listing of Toronto agencies.

 
Cannot really speak to what is right around the airport as I tend to hang in North York area. However, most offer out call, but likely will have some travel fee. Base fee structure is like the US, but a bit cheaper. Some will be largely all inclusive (CIM, MSOG and standard routine) for the hour rate. Some will have a markup for CIM or MSOG even at hour. RIM is often a markup but suspect if not mentioned then is a YEMV depending on the provider. They also offer longer sessions such as, dinner dates, over night and I suspect multi-day escort to show you the best the town offers.

 
Quality is about the same as DMV (probably not quite LA level on average) if you are doing in call so don't take all the ad pics as accurate or the description as accurate. I found the greatest variance with the C-agencies and the K-agencies more consistent with what I see here which allows me to set my expectations better off the ad I see. You'll also find a number of J-girls as well these days too.

 
On the indie side it looks like mostly Indian, Indonesian and Malaysian or native Canadian (mostly Caucasian but sometimes ethnic Asian) but no personal experience with the indie side of things. Easy to find a bunch of ads. Would expect lighter screening, than here in the USA, with the indies as well.

They have a site called TERB. It's similar to TER's forums, and has links to all of the agencies. That's where I would start.