This isn't as ugly as the Tempo interface. You can specify the name of the QuicKeys sequence or click that you want to run as a single parameter:
PostEvent "Reformat"
will run a click or sequence that you had previously given that name. PostEvent will accept the first match that it can find, checking the Hypercard-specific keys first, and then the Universal ones. If it can't find a match, it will beep once.
The Tempo interface will also work with QuicKeys. You might want to do this to issue a command key to a desk accessory, for instance. For QuicKeys only, a control key modifier can be specified in the first argument – use a lower case "c".