use one of the most vulgar word from your native language .
if he understands that language then use slang words

You can let your employees call you Lao Mi maybe. That's interesting and very Chinese style. That might makes you more easy to go with Chinese people.

If your employees call you 'Lao Mi', as Juneyao stated, then they are calling you 'Old Rice', and as everyone knows, nobody likes old rice (it gets used the following morning for gruel)

You can use the term 'lao da' (老大) which will make him happy, or, if he's trendy call him 'da ge' (大哥) which will make him feel like a gangster.

Or, if you want regular flavour, just call him 'lao ban' (老板), but this is a bit boring and he might start thinking about his mid-life crisis.

For absolute equality in the workplace (this is a Communist country after all) you should call him 'tong zhi' (同志). Just try to ignore the gay connotations.

Use his surname followed by 总. So for example, 李总. That's a respectful way and it shows his level of power and authority. I really don't think you can get away with calling your boss Lao Da or Da Ge (sorry Ludovico!)