Web UXUI Designer

I need to hire a web UXUI designer to build out mockups and user flows. The perfect person for this will be able to understand how people work and how websites should be designed and laid out in order to get the best possible response and to help users understand how to use it and avoid frustration and user confusion.

Someone who:
Understands the psychology of getting website to work
Understands how to avoid customer confusion
Can wireframe and mockup sites as well as design them completely for web development on a number of platforms
Has proof of work

Please respond with proof of work on this type of thing as well as the answer to this question to let me know that you read through my description.