How do I delete the demo data that was installed d

-- HikaShop version -- : 2.3.3
-- Joomla version -- : 3.3.6
-- PHP version -- : 5.4.32

How do I delete the demo data that was installed during setup?

There is no option to do that automatically. You'll have to either delete one by one the products/categories, or empty all the HikaShop tables via your phpmyadmin and then do an install of HikaShop again so that it puts back the default settings without putting back the demo data.