How to send files to the trash can without the confirmation dialog
Solution 1:
You can try this:
1) Open Pcmanfm (File Manager) and go to Edit > Preferences
For Lubuntu 12.04 to 13.10
Uncheck Confirm before deleting files
For Lubuntu 14.04
Uncheck Confirm before moving files into "trash can"
Hope this helps.
Solution 2:
You can also delete a file without moving to trash by using Shift + Delete shortcut.