I'm trying to programmatically create tasks/bugs on Maniphest: https://www.phacility.com/phabricator/maniphest/
but i can't quite seem to find a RESTful API that can do this.
am i totally missing out on something? or does there not currently exist one
Conduit (https://secure.phabricator.com/book/phabricator/article/conduit/) should work for you. There is a method called createtask (looks like https://secure.phabricator.com/conduit/method/maniphest.createtask/) that is exactly what you are looking for.