Sorry for dumb question....but: what's the safest way to update my wallet without risking to lose the coins I have in it?
You just run the new wallet version instead of old one; your coins are in your wallet.dat, and it's not affected by wallet versions (stored in different place).
Without having to manually delete any file or folder?
Yes, you don't need to delete anything; just run new wallet from any folder where you have downloaded it.
If you still feel unsafe - just backup your wallet.dat from your User\AppData\Roaming\FindCoin folder and run new client
