What's the name of this Heteroptera bug from Toronto, Canada?
This is, indeed, a Heteroptera bug. 

Luckily, this is not a kissing bug (which could be infected with Trypanosoma), but just an assassin bug, from the Species Reduvius personatus. Its common name is masked hunter.

Here is an image of the same bug, also in Ontario, from the Canada Pest Control website:



Source: http://pestcontrolcanada.com/5723-2/

And in this photo you can see the long rostrum, just like in your second photo:



Source: https://www.youtube.com/watch?v=9fIBT7IJHn8

Finally, to see an assassin bug in action (a different species, though), have a look at this video from the Smithsonian Channel: https://youtu.be/hXFRAmWiaa4