I want to delete a slideshow made by mistake! Help!

To delete a slideshow, right click (control click) on the slideshow in the My Projects section of the sidebar in Photos and click Delete.

It is strange, that we can create a slideshow from the File menu, but not delete it again without bringing up the contextual menu. It is a poor design. The same goes for folders and albums.

I would send feedback to Apple, that this is not user friendly, to let us create things, without an easy and obvious way to get rid of them again. Feedback - Photos - Apple

Control click is always the first thing to try to see if it will bring up a hidden menu. But that's also what we're here for!