The short answer is No, you can't just screw to the metal studs.
They're just too thin to provide much pull-out resistance.
However, with some wood blocking, this is standard construction for
office and schools. Both of these environments put much greater loads
and abuse on wall hung cabinets than you ever will. As one of the
previous replys stated, use a reversed piece of stud and wood blocking,
typically either plywood or 2X6. Cut a groove at each end on the face
to fit the little lip on the studs (the part that makes it a 'C' instead
of a 'U' shape) so the blocking fits up tight to the stud and doesn't
distort it. Screw through the metal stud into the blocking to secure
it. With plywood, screw on the face, with 2X6 you can screw through the
ends. If you have a lot to do, your local lumber can mill these up by
the pallet load for you. Put blocking continuously at the top and
bottom of the cabinets; you and your SWMBO could both hang on them and
they'll never come loose.

Brian Elfert wrote:
I am building some cabinets to be hung from as yet unbuilt wall.

I want to build the wall from 25 or 26 gauge steel studs (whatever they
sell at Home Depot/Menards) instead of woood studs.

Will screwing the cabinets into the metal studs be enough support?

Brian Elfert