After selecting a field in Konqueror, such the one where I am typing this post, it seems that the only way to de-select the field is to click outside of it. Pressing the Tab key will obviously just select the next field.

I would like to assign the Esc key to leave the field-- i.e. accomplish the same thing as clicking outside of the field.

It's interesting. But if that can't be done already, you should file an idea in KDE Brainstorm.

Done: #88581