So a sink the size of a dolls' house sink would be OK?I believe they can be any size. I'm pretty sure there are no legal requirements here in the US for the sink to be a certain size. If such regulations exist, I've never heard of them.
The size of the sink is determined largely by the available space in the kitchen and to some extent, the number of employees that would be using it. I think the general rule is 1 sink for every 25 employees. Again, some areas may have a regulation that determines the ratio of hand washing stations to employees. But, where I live, there aren't any such rules.
If you are concerned there may be some sort of legal requirement, contact your local health office and see what they have to say.
So a sink the size of a dolls' house sink would be OK?