I believe "polyurethane" is the finish you're looking for. It's used on furniture and floors.

There are a myriad of ways to apply it. I've always used either a brush (furniture) or a roller (floors or decks). However, there are ways of pouring it into a mold of sorts on top of the surface to be finished. Once it sets, I believe they take a torch to it to melt it and let it reset. This will release any bubbles and make the surface finish crystal clear. Mind you, I've never done this and might not be descibing it correctly. A little research will go a long way.

You'll see bar tops and some table tops done that way. The finish is tough as nails.