Good question. Well, in a salon, there's the salon owner who gets a percentage of everyone else's take because the owner provides the salon and furnishings. The salon owner also pays the commercial property tax, insurance, utilities, maintenance. Those who do hair, skin, nails provide their own products unless they have an agreement with the salon owner to purchase their product from the owner at wholesale cost.
Basically, as I understand it, the hair, skin, or nail people rent or lease the spot from the salon owner to conduct their business. This said, I think tipping is in order, as they get to keep this portion for themselves. As a rule of thumb, I tip anywhere between 10-25% depending on the cost of service and my satisfaction level.