I just now finished assembling my first conversion, but i noticed that when i pedal the rear hub/cog/chain make click-clack noise similar to the one a free-wheel makes when not coasting. i thought fixed gears where supposed to be silent, how can I remedy this?

Have your tried measuring your chainline to make sure it is straight? Even if you chainline is money, sometimes you will still get noise as parts wear together. Once they wear in a little, the noise may decrease. Do you have the chain well lubed?

Lube your chain.

put your chainring on the inner side of the cranks.

You'd need to diagnose this as a chainline issue first, and then verify that this would actually correct the chainline. Unless you know something about the OP's setup that we don't?

I'm making radical assumptions, but using a john edwards style elimination process, I can guess...

He said it is his first conversion, which tells me that he may be inexperienced in building up bikes.

The language used doesn't scream mechanical experience.

He mentions he thought fixed gears were meant to be silent. which basically sums it up.

If it is your first conversion, a straight chainline is the point where the distance from cog to frame centre is the same as chainring to frame centre. Moving the chainring to the inner side of the crankarms will usually bring the chainline close to perfect on a conversion.

see, I'm psychic. (unless I'm wrong)

Chain and cog need to wear in.