Can I put two 240V 10 Amp outlets on a 240V 20 Amp circuit?
Yes, you can put multiple properly rated receptacles on a circuit, regardless if it is 120V, 240V, or 120/240V. 

I don't know why the word Canadian is in that description, but a duplex 6-15R is perfectly fine in the US.

A 20A circuit with multiple receptacle outlets can use either 15 or 20 amp receptacles.