One would think that in a centrally planned economy that if the government needed to take a cut of the production they would just pay the workers less up front, as opposed to collecting taxes later. Is that how it generally worked?
The Soviets relied on a few different taxes but the primary tax was along the lines of a modern VAT tax called the turnover tax. They also had a food tax and a childless tax, and other minor forms of taxation.
I'm not aware of any income tax equivalent to the US system of taxation.
An Economic History of the U.S.S.R. by Alec Nove