I am not really sure you can delete a city but I think you can delete the entire region from the start screen.

You can transfer money between your cities that are within the same region (also power/water/waste/etc) but it's somewhat glitchy at the moment and takes a bit of time to complete.

I tried to add both you and Joe last night but it couldn't find either of you. Not sure if that is due to the server issues or if I have your name wrong. Mine is Klaus9000