Hikashop Category and Product Display

Hi,
First of all sorry for this post. But, I'm still struggling to understand and control the product and category urls of hikashop.

The joomla menu of my site home page is set as product listing and the associate category set as root. When I click on any of the product listed there I see the SEF url is like:
"mysite/product/product_id-product-name"

I have 6 product categories and thus I created 6 joomla menus which list all products from specific category. Thus I see the SEF url is like:
mysite/menu-alias/product/product_id-product-name-alias

1. Do I need to assign every hikashop product to a joomla menu (like joomla article) to have a unique SEF? I don't want multiple SEF in my site for a single product

2. what does the product "Canonical URL" do in hikashop?

3. I'm still confused about the display and control on their views. I read the documentation quickly and thought it would be great if anybody could explain the concept a bit differently. Sorry, for raising this point as I'm just working on Hikashop.

Thanks,
Kollol

Thanks Nicolas.