Well there is "Matti Meikäläinen" which is the Finnish equivalent of John Doe.
Also, Matti Virtanen is the most common name in Finland even though the Korhonen family has beaten Virtanen as the most common surname in Finland currently.
I would also point to Urpo Vähäranta as a rather "Finnish" name. (Yes, that is a real name and he is a former athlete who was at his prime in the 1950s winning medals in running contests.)