Can I find a job in Hong Kong on a tourist visa?

Yes, you don't need a tourist visa, as long as you don't work illegally.

I know some people who come to Hong Kong to look for jobs on visas such as visiting relatives, and then apply for work visas after they find them, so that they can stay and work in Hong Kong.

However, the time of tourist visa is very short, so it is best to make some preparations online in advance.