if you have a great page of your business on facebook and several peoples follow it. you can get potential costumer on facebook, you have to share regularly info or pictures about your product or services.more sharing can attract more people and they convert in form of your costumers.
Yes you can find potential customers on Facebook. You can get more customers If you create a paid ad and set the right targeting. It should target certain people of certain age and certain location, maybe you can define your targeting group by occupation, interests or statuses.