They powder coat most metal parts. You're not going to find that in Canadian Tire.
Plastics are usually dyed at the manufacturing level. Again, not going to find that at Canadian Tire.
If you want professional gun paint. Check out DuraCoat from Lauer Custom Weaponry.
http://www.lauerweaponry.com/
Cheaper option would be to use Testors Model/ Hobby paint. Find it in spray cans at hobby shops.