I've not seen Kumihemo before. However, looking at the results of the
Kumihemo process shown in the powerpoint presentation reminded me of some
braiding my own children did for awhile, without a loom. It was done with
lengths of embroidery thread tied so each pair ended in a loop. The loops
are held in both hands and switched back and forth to create a braid. It is
very easy and fast to do, requires no equipment except some sort of anchor
(like a safety pin), and can be learned by younger children.
I looked up fingerbraiding and found a photographic demonstration of the
process at http://artroomk-6.tripod.com/spinning/spinactivity.htm (I could
find no attribution for this, it appears to be put up by a classroom
teacher). I found a history of this technique at
http://www.bumply.com/Medieval/finger.htm Copyright Andy Goddard 1997 as a
technique used in Medieval England. Some demonstrations of variations and a
short bibliography: http://www.stringpage.com/braid/fl/fingerloop.html . At
the time, the people who taught us told us that this had been used by
sailors also to make rope, but I don't know if this is accurate since I've
never investigated the background. There are many more links by searching
for finger braiding and fingerloop braiding.
A comment about the appeal to children: My children were participating in a
local theater production that used many children and ran for about 6 weeks.
The children spent a lot of time waiting in the green room between their
scenes. One girl started doing this braid to pass the time and soon almost
all of the children in the show (ranging in age from 8 to 14) and many of
the parents supervising them learned the technique. They created hundreds of
braids which they started selling in the lobby of the theater as a
fundraiser, and then donated the proceeds to the Playhouse.