I need a visual designer to help transform our vision into great, original, appealing interfaces. This includes traditional web apps, iOS apps, Android apps. I would like someone whose train does not stop at the Illustrator file, but can execute with HTML, CSS, etc. No programming beyond that is required, but comfort working around and alongside working code is a requirement. We have found that small iterations work better and faster when the person visualizing the design is involved in the execution as opposed to handing a static picture to developers to implement. If something is working, but could be improved visually, you would handle that, with developer assistance as needed.
Up to this point, visual design has been done by developers and functional UI experts. It is time to level up visually and that would be your role.
Workflow is likely to start with a general (or sometimes vague) idea and through lots of back and forth, arrive at something great. At that point, depending on what it is, you would execute that visual design, then hand it off to a developer to hook everything up.