Wearing kicking boots will increase the damage done by kick attacks (by 5), increase the distance that kicked objects travel, and will increase the chances of kicking down doors to 100%.
Unlike the other randomized boots, they are made of iron; they can be identified if wearing them increases the failure rate of your spells, or if rubbing them on a touchstone produces "scritch, scritch." You can also identify them becausethey are prone to rust, by the attack of a rust monster or by getting them wet.
Another method to identify kicking boots is simple -- test kicking a suitable object (a rock will do) without the boots, then while wearing the boots. It will travel farther with the boots on if they are kicking boots. These boots may also be identified via price identification, if the boots cost the same as elven boots and when wearing them you don't get the message "You walk very quietly," they are kicking boots.