Hello, I am sort of new to cron jobs, I have a cron job running everyday that no longer needs to.

How do I cancel it?

if you can see your cron jobs with "crontab -l", you can cancel it by
typing "crontab -r".

But does that remove all jobs?

How do I say I want to cancel only 1 job. Is there a .conf file or something I can remove the line from?

Also, what about canceling a rsync job?

use:

crontab -e

to delete the line for the job you want to remove, then save and quit.

yes
you can use crontab -e
and you can edit your cron...
ex:my cron

#00,30 8,9,10,11,12,13,14,15,16,17,18,19,20,21,22 * * * /export/home/lsav/MAKING/cronsas 1>/dev/null 2>/dev/null
3,18,33,48 3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23 * * * /export/home/lsav/gratika/AA/asr 1>/dev/null 2>/dev/null
40 23 31 7 * /export/home/lsav/GINTINGSERVER/AA/kirim.sh 1>/dev/null 2>/dev/null
0,15,30,45 * * * * /export/home/lsav/GINTINGSERVER/AA/cpu_sar 1>/dev/null 2>&1

or....you can remove line in your cron if unused in future.