Well, "skill" can't be in a tabletop RPG, or anything that isn't active time. Only "wisdom."
For example, I consider it "skill" when I pull of a manual 10 hit combo in a fighting game, or accurately shoot someone in the head in a FPS. However, I consider it "wisdom" when I know I should only run 3 of card X in my deck, that I should max out feat Y ASAP, or that I know that a boss is weak against fire.
Even if you don't agree, skill is a vague term. You might have to be more exact about what you mean.
Edit: a exception I just thought of is Sabin's Blitz from FF6. Since you have to have the skill to input the command properly, or he won't attack. Even if that isn't a active time command it still requires skill.
Edit 2: It's a shity idea, but maybe you could have a bob-it/Simon says device packaged with your game, and like a level 2 spell requires you to get 6 actions correct with it?