Rose has said that it is impossible to make a perfectly smooth praline paste without specialized equipment, and I believe her.
One thing that does work with some recipes, is to make a caramel version of the recipe (dissolve the caramel in liquid in the recipe) and then add an equal weight of hazelnut paste. I don’t know if hazelnut paste is any easier to find than praline, but that’s how I always do it. For instance, for the praline silk meringue buttercream in the Cake Bible, I make the caramel version, and add hazelnut paste. That way I have one less (pricey) ingredient to stock.
I bought my hazelnut paste from lepicerie.com, it is perfectly smooth and delicious (but they are NYC-based and I don’t know how shipping to Canada is).