The trash can in OS X is great when you're not totally sure if you'll need a file again, but more often than not, when you delete something, you mean to do it. Thankfully, in El Capitan, you can skip the trash can and instantly delete items with a keyboard shortcut.
To skip the trash can and delete items, select the files you want to get rid of, then tap Option+Command+Delete. This bypasses the trash and removes the files forever. It's not much, but it is one of those handy, tiny improvements that makes El Capitan better.