Unable to delete apps in ipad mini 2 after upgrading to iOS8.3

If this is in the Purchased tab in the App Store app then you can't (and have never been able to) permanently delete any item from your account's purchase history, and hiding them there is also unlikely to work on iOS 8.3 (there appears to be a bug that means that they reappear when you exit and return to the Purchased tab).

To hide them from the cloud so that they don't show for redownloading you need to use your computer's iTunes : Hide and unhide purchases in the iTunes Store - Apple Support (and on the current version of iTunes there is another bug that means that the 'x' doesn't show on an apps' top left corner when you hover your mouse pointer over it, but clicking there should still hide it).

To delete a downloaded app from your iPad : press and hold any of the apps on your iPad’s homescreen and after a couple of seconds or so they should start to shake. Then press the 'x' in the left corner to delete the ones that you don't want, and when you've finished deleting press the home button so as to stop the shaking. If you don't get the 'x' on any of the apps that you've downloaded (you can't delete built-in apps) then check that Settings > General > Restrictions > Deleting Apps isn't set 'off'