Constantly using a skill?

It seems to be VERY tedious to use the same skill by having to click the small Skill Box, clicking the skill, and then clicking your enemy EVERY time you want to use it.

Is there possibly a way to set a skill to a Hotkey in battle so you don't have to continuously do the same thing every time you battle?

Yes there is, all you do is open your skill list by pressing alt+V or by clicking the icon right of the attack button.
Then click on the skill that you wish to make a shortcut for, then press one of your keyboard's function keys eg. F1, you should then see "F1" in light blue beside the skill you chose.
Next, when you enter battle press the function button you assigned to your selected skill and click on an enemy target.

You can find out about other shortcut keys by clicking the question mark to the top right of your screen.

Thanks so much. :)