There is no difference in the principles behind pruning dwarf JM's as opposed to full sized JM's.

I am assuming you want to reduce the spread, as the encroachment on the walk and on other plants seems to be the issue. I find the best way to do this is from inside the canopy of the tree, getting down on your hands and knees and crawling around a bit :-)) You want to remove branches that extend beyond your desired size limitation. Not necessarily entire branches emanating from the trunk but partial branches from the outside in, removing them back to where they emerge from a larger branch.

Make sense??

You should also remove any obvious dead wood at this time and you can thin or overall lighten the canopy as well, if you desire. It is just important to have a very light touch when you do this and take off no more than a third of the tree. I find it helps to stand back and take a look at your progress often....and from all views :-)

Now is a perfectly reasonable time to do this.

gardengal,

Thank you for the detailed and helpful advice.