IMPORTANT SAFETY NOTICE:
That printed circuit board is the innards of an ELECTRONIC FLASH UNIT!!! High voltages may be present.
THE CAPACITOR, IF CHARGED (AND IT PROBABLY WILL BE) WILL GIVE A NASTY, DANGEROUS ELECTRIC SHOCK IF YOU TOUCH ANY PART OF THE CIRCUITRY.
At a minimum the flash can go off in your face, causing a temporary burn spot on your retina. (This happened to me. If I do this again I will put some black gaffer's tape over the flash.) Proceed at your own risk. You have been warned. This article is merely a description of my experience. No responsibility taken for what you may do.
An excellent, elegant optical viewfinder for free
Inspired by Jay Javier's most wonderful FED-1 & ZORK-1 SURVIVAL SITE I set out to make a viewfinder following his recipe, which involves taking the viewfinder lenses out of a disposable camera, constructing a box to house them and a foot to mount in the camera's accessory shoe.
The first step: stopping off at my local 1-hour photo and begging for a camera, and popping it open:
The thin plastic molded front and back of the case readily split apart, revealing the chassis with everything mounted on it.
(A few irrelevant observations on the camera: No rewind -- the film starts out on an open spool, and as pictures are taken it is wound into a standard-type cassette. The single-element meniscus lens is held on the chassis by a simple plastic bayonet ring. The focal length of the lens is 28mm; the field of view of the finder corresponds to 35mm, presumably allowing for photographer's aiming errors and allowing bleed (surplus image) for cropping to borderless prints. The film 'plane' is curved.)
I was very gratified to see that the entire viewfinder is a single piece of molded plastic:
which pops right out.
Other models:

The Kodak on the left has the same viewfinder as the Kodak model dissected in this article. The Fuji model on the right has separate finder lenses and requires construction of a body as described in Jay's article (linked above).
All the tools I used:
An apartment-sized mini-vice to hold it while sawing off surplus plastic, a piece of tape to cover the lenses while in the vise, an Exacto sawblade, the flat file on a Leatherman tool to notch the front lens.
The finder covers the same view as my $200 Leitz 35mm brightline finder. The cost: $0. It fits snugly and securely on the Kiev, and gives a clear image with minimal parallax. It fits well with the elegance of the Kiev it sits on. (I could file a notch for the shoe's stop pin to allow the finder to be pushed further into the shoe, but I don't think that is necessary as the top deck of the camera does not block the view.)