canonical url on HikaShop

No. I don't see how we could implement that.
It would require that for each page we parse all the menus of Joomla and look for the options of these and then, if we would find other menus going to the same page we would have to somehow decide which one is the main one or not. That would mean a huge hit on the page display. Furthermore, the Google algorithm for page parsing already decide on that on its own so the value added to such feature is really low while the cost of implementing it is high. It doesn't sound like something we would implement even as a plugin in the short to middle term.

It's on our todo list.