If you do some research on line you will find a list of examiners who do Canadian medicals all over the world. Your nationality should have no bearing on being able to do a Canadian or FAA medical overseas.
Khosla, H New Delhi India 91-11-2 46-9 2544 English
Masrani, P Mumbai India 9122 2490 1066 English
Mehra, A Mumbai India 91 22 2642 5335 English
Puri, SK Mumbai India 9122 2634 7257 English
Sridharan, A Chennai India 44-4 2-05 7343 English