How to use Character Viewer with only keyboard and no mouse?

I'm looking for a mouseless/mouse-free solution. And I want to use the whole Character Viewer-- not just certain characters. I can open the Character Viewer with CTRL+CMD+SPACE, but it doesn't have focus, so it seems I have to use my mouse to select anything inside it. How can I give that window keyboard focus without using my mouse? And then how can I copy characters from that window without using my mouse?