You should have no trouble booking a one-way flight to Canada if you are a Canadian. But you may have trouble returning to the DR unless you are a legal resident. You may be able to book a one-way return ticket but you may not be allowed to board in Toronto. if you are a resident, no problem, however.
A couple of years ago my wife booked a return to Toronto on Air Canada. Upon trying to return to the DR the airline insisted she book an onward ticket to the UK - no cedula, UK national. That ticket cost over US$3,000.