Looking for a job on tourist visa

Hi,

I know there have been many forums about getting a one way ticket to vietnam and looking for a job on a tourist visa.

Can someone please let me know how difficult it is to get through to vietnam from Australia on a one way ticket?
And..if I was to look for an english teaching job on my 3 months tourist visa as it is difficult to even search for a job while in Australia and apply for a working visa. Because I have heard that you are unable to transfer your tourist visa to a working visa, if I have found a job but a working visa is required would I need to leave the country and come back to the immigration and apply for a working visa?

If there is anyone that have moved from Australia to vietnam and was looking for a job on a tourist visa. Would you please inbox me or even let me know. Because I am starting to find it becoming difficult to move.

Thank you