Dealing with left-padding using RSA

[kit-ty-kate]

According to the Nocrypto.Rsa.decrypt documentation:

[decrypt ~mask key ciphertext] is the decrypted [ciphertext],
left-padded with [0x00] up to [key] size.

I have several questions on this:

• I don't know why this behaviour is noted here but not in encrypt which does the actual padding.
• It says [key] size and maybe I'm missing something on how works RSA (most probably) but only [key] size / 8 is actually used (e.g. 256 for a 2048 key). Is this documented anywhere ?
• Is there a way to remove them properly ? Do we have to pad ourself the string before encryption to be able to handle the string format ?

EDIT: Ok just realize how dumb was my second point but maybe there can be something in the doc saying something like [key] size (in octets) to be a bit more precise for noobies like me.