This is how :
- on the desktop, right click and choose Create Launcher
- fill the blank :
Name : name it as you wish : Trash Can, Recycle Bin
Command : nautilus trash:///
Comment : your choice
- you can click the icon on the left to change it,
- click close
There's an alternative way :
Use gconf-editor then go to /apps/nautilus/desktop and checkmark trash_icon_visible.
While you're there you can rename by open the trash_icon_name, change value type to string then type its name.
keyword : trash, recycle bin, shortcut, on desktop, command line