I'd simply like to know how to delete an entire line moving forward opposite of deleting an entire line backwards (cmd + delete). I know to delete individual characters moving forwards is fn + delete but what about the deleting the entire line itself?
You can use Control ⌃-K to do this. This is one of the many key bindings that OS X borrows from emacs by default. Others include Control ⌃-A to go to the beginning of a line, Control ⌃-E to go to the end of a line, and Control ⌃-D as an alternate forward-delete.