With my Hotmail account on my new iPad it seems that I can only delete junk mail by opening them first which I don't think is wise. However, on my main PC I am able to delete them without opening them which is, of course, best.

Can anybody please advise me how to solve this problem? Thanks.

Within the Inbox, swipe the email from left to right (or vice versa) to bring up a "Delete" button.

You can swipe left to right on the junk emails in the list view on the left of the screen (in landscape view) and that will open a Delete button, without the need to open/view the emails.