CSS STYLING

-- HikaShop version -- : 2.5.0
-- Joomla version -- : 3.4.3
-- PHP version -- : 5.4.38
-- Browser(s) name and version -- : Chrome 41

How can I access and edit the following css file via the backend:
/media/com_hikashop/css/frontend_custom.css

Some items need styling in this file, but once I access it via template manager there is not much to style (i.e. padding, margins, etc). So it seems like I am trying to access the wrong file.
/templates/kallyas/css/templates.css.php

Hello,
You'll find it via "Hikashop->System->Configuration->Display->'CSS tab'" by using the "Front-end CSS File" option.

Okay got that one - thanks!

And where do I access this to do changes to change some styling?:
/templates/kallyas/css/template.css.php?src=..%2Fjstystem-..%2Fcss%2Fbootstrap-..%2Faddons%2Fsuperfish..............

you'll just have to edit the file /templates/kallyas/css/template.css.php through your website files.