There are basically 2 things which are the crux of a worker visa application, 1) that is a bona fide job offer that the applicant is qualified for and 2) that the applicant has sufficient ties to their home country - which could reasonably satisfy the officer that the applicant will return to their country at the end of their authorized stay.
For proof that the offer is bona fide, and that the applicant is qualified, I would suggest to submit proof of any relevant education, i.e proof of diploma from hotel school, proof of language training, especially that of english or french, but other languages can also be relevant, any other certificates.
For proof that the applicant will leave at the end of their stay, this is a little trickier, as there is no time machine which will take someone to the future to prove this. If the applicant has familly that helps, property, or job prospects, those would be considered sufficient ties. However, often jop prospects are compared directly to canada's.
Best way to proceed I believe would be to strengthen the job qualifications aspect, if this is strong and they have doubts about the intent to leave, they should call an interview. Where if the applicant behaves normally, is honest and straight forward, chances are good, for instance, the person should have a plausible plan for what to do when the contract is done. Perhaps an offer from a hotel upon chain upon their return would be good, or having a good answer i.e " I plan to save up and open my own XXX business in the dominican republic" or "foreign experience is looked highly upon, I can secure I higher paying job when I return from Canada.
I would have to take a look at the application form, and required supporting documents, but that is for the most part what you need. There is no mandatory interview, so the best you can do is make it look great on paper.
I believe that there is about a 50-60% approval rating for work permits, and about 65-70% approval rating for visitor visas.