No not really... the two hardest kicks are the pretty basic, yet powerful, thai kick and the crouching capoeira kick. Im not sure what your spinning kick looks like, but I will say that whenever a fighter jumps in the air or does some fancy style a lot of power is lost. Not sure what the "heel kick" you mentioned looks like, but if it is like a foot jab, it sure as hell wont knock many people into a dizzying state.That stuff is for the movies.
Besides to do any of these kicks, one would have to be wearing minimal clothing, which really is not feasible in TES. With that in mind, it hurts enough kicking someone's elbow, let alone a dragon.
A heel kick is exactly what it sounds like. It will give you a concussion, knock you out, or kill you if it's well placed. A foot jap would more just be the "fast" attack, whereas a heel kick would be the meat club that brings your opponent off their feet. It's ironic that you say "thats in movies" because Hollywood tends to propagate the idea that fist fighting is harmless, wheras it most certainly is not, and kicking is even more destructive.
Frankly I find the idea of killing dragons in the first place to be pretty stupid. These are firebreathing creatures that weight 10 tonnes and are covered in thick scales, the premise of killing one in the first place it pretty ridiculous. I don't think HTH would make much of a difference. I never used HTH in any TES games because HTH was never fun. HTH should include the ability to disarm and knock opponents down, and should provide both kicking and punching. I'd say that people who use HTH should not be capable of harming dragons in that way, HTH should predominately be for fighting human(oid) opponents. Besides, it's not like it'd be their only means of killing a dragon.
Heres a few examples from youtube of a good hard kick, those are with padded shoes and padded helmets too and it's still enough to concuss and knock out.
http://www.youtube.com/watch?v=e4fwpm1G_fE&feature=related
http://www.youtube.com/watch?v=Qqn5_enzM7Y (that kid's school grades must have dropped substantially 0.0)