For teleportation, there is a white dot in the center of the screen in VR mode that determines the teleport destination. You can move your head to place this dot at a place where you would like to teleport to, for example on a floor nearby, and the teleport should take you there.
Using controllers for walking is not supported (in general, not just with Mixed Reality). Walking in VR without physical movement of your body causes nausea no matter if you use keyboard or controllers. This is why so many VR experiences use teleport based navigation.
At this moment we don’t have plans for more sophisticated controls in VR. There are too many different headsets and controllers in use and also WebVR browser support is changing too fast for us to be able to provide such support.