The product id is usefull to redirect the customer to the good page
Whet you can do is set the product name instead of the product alias for the url.
Try to replace the code:
$link = hikashop_completeLink('product&task=show&cid='.$this->row->product_id.'&name='.$this->row->alias.$this->itemid.$this->category_pathway);
By:
if(empty($this->row->alias))$this->row->alias = urlencode(strip_tags($this->row->product_name));
$this->row->alias2 = $this->row->alias;
$link = hikashop_completeLink('product&task=show&cid='.$this->row->product_id.'&name='.$this->row->alias.$this->itemid.$this->category_pathway);
$this->row->alias = $this->row->alias2;
in the view "product / listing_img_title" (or another depending on which listing you are using), you can edit this view in "HikaShop > Display > views".