Re: "Yes there is kicking and punching in Aikido..."
Chris, my two penneth.
Firstly Aikido is not primarily a striking art, emphasis primarily.
Secondly, as I was taught, low kicking was part and parcel of practice. The main reason it was done was to get you used to ma-ai. It also had a secondary reason which was to be looked at as no different to atemi. Thus there are low points which can be 'attacked' and thus usually by your foot. I'm sure if you look these points up in the annuls of Aikido terminology you will come across them.
I was also taught that the movements tracing back through samurai times etc. would rule out much high kicking as there is nothing more tasty to a sword wielding samurai than a nice extended leg. So be it. Food for thought.
So in conclusion I would say there is no reason why you couldn't use your feet in such a way but it all depends when, why, and how. It wouldn't however be a primary part of Aikido.
O.k. ended up three penneth.