The Right Time?

How to if not tell, show to someone that you have a feeling for them?
Even though you know chances of that person to like you back are close to none. Without jeopardizing the friendship you have with that person. Is the risk worth taking? When is the right time to do so; avoiding it from being too soon or too late. I often ask these questions to myself. It's easy for me to like someone but liking isn't enough to bring them out of the friend zone. I'm not sure if I'm looking forward to start dating at the moment. I've come across this phrase before " To move on from someone is to get it on with someone new ", true enough but how can one be sure getting on with someone new is not a form of rebound? When is the right time to move on? Not everyone has the same dwelling period if I must say. So how to be sure if that person has moved on for good? Is he or she still clinging to their past? Being in a rebound relationship, being the 'victim' of one sure is suck. The reason why I'm writing all this is because I think I may have started liking someone who's halfway across the world. Who I only met online but we've been talking everyday since i can't remember. The more I talk to him, the more I find him interesting.