Just in case, here we go:
In your template.css, go to line #6462. Change that from
#hikashop_checkout_page #hikashop_checkout_cart .row0 td {
background: none repeat scroll 0 0 #FFFFFF;
padding: 20px;
}
to
#hikashop_checkout_page #hikashop_checkout_cart td {
background: none repeat scroll 0 0 #FFFFFF;
padding: 20px;
}
So, just remove the ".row0".
If you want less padding around the individual table cell contents, reduce the "20px" to something less, e.g. 10px.
Not sure, though, if it'll be safe from being overwritten back to the old state or complete deletion once you update your site template or so, because the file name doesn't appear like it's a safe override but rather the original template CSS...
Good luck.