Dumb question. I can't figure out how to make a mesh (quads or triangles like a pie) automatically so to this flat face so I can then pull the center to round it out (like half a sphere would look). I don't want to bevel it. Isn't there like some Hot Key combo that does this?
As @ideasman42 points out in this answer, you can press:
As @David said in this answer, you can use grid fill by:
Delete the face > Select the vertices > Press E to extrude then Left mouse click > Press Alt+M and select collapse.
The better way would be to Delete the face > Select the vertices > Press E to extrude > Press S to scale. Scale it way down > Left mouse click > Press Alt+M and select 'collapse'. Then hover your mouse over the larger part of the new face and press Ctrl+R and scroll your mouse wheel to add a bunch of loop cuts and Left click when satisfied. This will make it easier to accomplish your half dome.