The HUD in Shadow of Chernobyl was designed for low-resolution CRT monitors and looks rude in screenshots of an otherwise aesthetically accomplished game. I don't know a way to hide the HUD using console — there are two
hud_ commands which control the crosshair appearance (possible in the options) and
HUD_info just informs that the HUD is on.
While disabling the HUD is possible by editing the game's texture files (see this mod, the game has to be of course restarted), playing entirely without the heads-up display naturally only is an option for the most dedicated players.