Ukrainian here. I've only seen 4m kitchen once in my life, and it was in apartment in 120 y.o. building. In all the USSR-era apartments the kitchen was at least 8sqm.
Here you have a typical plan of block khruscheba: http://ic.pics.livejournal.com/volgodim/14339505/26623/26623... I've seen quite a few of those. 5.8 m^2 kitchen. All over Russia.