If somebody can make the mouse "target" the current tile it's hovering over, then it might be a good first step. Start with a modification that shows X, Y, with mouse positioning. Then look into changing the targeting mechanics from entity based actions to tile based actions. I would suggest keeping both systems working and having a toggle in the skill type to determine tile based targeting or entity based targeting.
This could be all wrong but it's just from what I understand without actually looking at any of the code.