There is a Dominican woman(lotusflower) who has posted on DR1. You should be able to find some posts by her. She is a Dominican that did receive a visitor's visa to Canada and I know of a family that did also. In both case I beleive they already had visitors visa to the USA.
My wife Yris, who is now a Canadian citizen applied to visit before we were married. She had money in the bank(enough by any standards), several houses, land, a business(private school), spoke English and French, educated...etc, and they still refused her a visa. So the probability is very low, I wouldn't say impossible but certainly highly unlikely.