I can only help with Japanese, but I would think it would be similar.
The FreeBSD scim-anthy port installs all necessary items, anthy for conversion between kana and kanji scim and scim-anthy for input.
I would guess there is probably something that works equally well for Chinese.
You will also probably need a terminal to handle UTF-8 or other Chinese encoding--I use mlterm for UTF-8 (in FreeBSD, and in some, though not all Linux distros, I can set my LC_CTYPE to en_US.UTF-8 and Japanese will input properly--with NetBSD and some other distros, some, but not all applications, require me to set LC_CTYPE to ja_JP.UTF-8.
I know this is little help, but I did want to encourage you--I am sure that if Japanese is relatively easy to input, Chinese will be too, though of course, your character dictionaries will be far larger, as Japanese can make use of phonetics. (I think I once read that the literate Japanese knows 1500 characters vs. 5000 for China.)