Okay, I am going to ask a stupid question again. If I wanna let someone else to help me with configuration stuff, but they can only access via ssh, how can I create a temporary ssh account for them, which in a sense is safe to me? Can I just give out the ssh account of one of my hosted domain?

type "adduser" and then when it asks for what their home DIR is set it to your home DIR.

Regards,
Shay Bekman

For admin work you will most likely need to give them the root password which you can then change when the job is done.