It is legal according to the HTA as long as you have 1 mirror, you should be fine. Print out the statement in the HTA if you're paranoid
Windshield wiper, mirror
66. (1) Every motor vehicle other than a motorcycle shall be equipped with,
(a) a device for cleaning rain, snow and other moisture from the windshield so constructed as to be controlled or operated by the driver;
(b) a mirror or mirrors securely attached to the vehicle and placed in such a position as to afford the driver a clearly reflected view of the roadway in the rear, or of any vehicle approaching from the rear. R.S.O. 1990, c. H.8, s. 66 (1).
Exception
(2) Clause (1) (b) applies to all motorcycles except those manufactured in or imported into Canada before the 1st day of January, 1971. R.S.O. 1990, c. H.8, s. 66 (2).
Can you see the rear in the mirror? If yes, legal.