Is there any way to skip Combo Chicken lessons?

According to this wiki, Combo Chicken cannot be skipped (emphasis mine):

Combo Chicken can be started as soon as you reach Santa Luchita, but cannot be finished until Juan has learned all Special Moves.

For what it's worth, this is widely considered an annoying part of the game, and fairly repetitive and difficult (so I wouldn't blame it entirely on a lack of fine motor skills).

However, I found these threads which make a couple of suggestions on how to beat it, which include:

• Pushing Poncho back against the wall - this should help with targeting him and landing the combos
• Taking your time - the buttons don't need to be pressed immediately, so taking some extra time to make sure you have the directions correct can help ensure the combo lands correctly

I also found these videos which may be of some help in figuring out exactly what the combo is, and providing some insight into how to land them correctly.

Based on my personal experience with Guacamelee, this part of the game is, erm, challenging. I fancy myself as having played a few fighting games in my day, but this part of the game definitely took some time. For me, I just kept practicing, and deliberately trying to push the correct buttons in the correct sequence (that was my main problem). So I would recommend beyond the advice from the sources above, just try to be really deliberate in your actions, take your time, and you should be able to pass it after a couple of tries!