...How do you use the ball throw ability? It's the one reason why people hate having me on their team.
When you entered your first Huttball-match, a "Throw the Huttball" ability was added to your quickbar. If it isn't there, you can find it on the General-tab of your Ability menu, from where you can then drag it to the slot and the quickbar of your choosing.
When you actually do use the ability (can only be used when holding the ball), you will have an aoe-target that you have to click on the ground. The ball will be thrown to the area which you clicked. You don't have to target any specific player, just click the ability, click the ground with the huge green target cursor and you're done.
It is preferrable that you bind the ability to an easy-to-reach hotkey.