In the Feature or Epic Grid click on More Actions

Then click on Mass Move

Then click on Mass Delete View

You will see the warning model:
Deleting the selection item(s) will move them to the recycle bin. It will remove all child relationships as well.
Example: Deleting an Epic will also delete all Capabilities, Features and Stories linked to it.

You must select a Program before you will see any items for "moving" (to the recycle bin).

One quirk on the Mass Delete page is that if you click the Next button to the go the next page, Jira Align does not save the checkbox selections so click the Move to Recycle Bin button each time before clicking the Next button.