This is not a technical term. In fact, I've never heard anyone else say the phrase in regards to kitchen design. It's something I found myself saying over and over again when I saw a wall that I wanted to take for a specific purpose. Most of us have a wall in our kitchen that screams, "Show me off," "Do something with me," "I could be so much better!" - The opportunity wall.
As kitchen designers we see it immediately after walking into a kitchen for the first time and almost everything else falls into place based on this wall. Sometimes it's easy to make work and sometimes it takes a little more finesse.
In the above example we all felt it was best to split the windows in order to have them flank the range and hood. This was the ultimate opportunity - Pretty hood and back-splash as well as windows to bring in some of the outdoors.
The pictures above represents a small struggle between the homeowner and myself. It was a bridge that needed to be crossed lightly but I felt very strong about getting rid of the window on the back wall. Keep the window and the kitchen doesn't make much sense - Delete the window and everything falls into place. It was worth it in the end to push a little bit - We all ended up very happy.
The opportunity wall doesn't only have to be pretty (although it's one of the goals), it should also add functionality to the kitchen. Perhaps it provides more counter-top where you need it, creates a better work flow or let's you vent your hood directly to the outside. It should be the wall that gives you the chance to have a great work space but also the wall that let's you have some fun and let your kitchen do some showing off.