Answer to first question:
After clicking on the map tab, if you click on a red ray you will see it turn blue and it will start to map the possible caches you can find to turn it from red to green. You have to mouse over the cache bubble to see details of that cache and you can click on it to bring up the cache page. By dragging and zooming you can project the ray out as far as you need. I tested it out to over 2000 Km.
Answer to second question:
So far, I have not seen anything that shows a list of possible caches. If you click on the table tab, it will list all the caches you have actually found that fills the green rays. It does not list caches needed for the red rays and only lists a 0. I believe this tool is still under construction so I cannot speak for features that may be added in the future.