Just get a cheap, hand crank fuel pump. Stick a tube into the top of your gas jug, and attach it to your pump. Pull the fuel tube off your needle valve, and stick it on the other fitting on your pump. Pull the tube off your muffler, and hang it over the side of the plane (onto a rag). Crank the pump until fuel goes into the tank, and keep cranking until fuel squirts out the muffler tube. Put the tubes back onto the engine, put the lid back on your jug, and you are ready to go.

There are special can fittings, and fancy fuel delivery systems, but you really don't need them.