All of Sanji's kicks (except for the Air Force kick where he shot Luffy off of his leg) are named after areas of a body for preparation as food. With that in mind, I propose Echine. It is a way of preparing pork that encompasses the shoulder and the ribs. I figured it would be a spin kick with the heel of his foot connecting with the area under the opponent's underarm. It would be effective for disarming someone who is armed or, if there is a little extra follow-through, disabling someone's arm completely.
As for a potential combo kick, I think if Sanji jumps into Chopper's antlers (in Horn Point mode) with his legs straight out or spinning and they rush toward an opponent, they could clean house pretty well. The name…maybe the snow plow or, with the food parts theme, ground chuck, filet mignon, or veal chop. It would be helpful if I knew more French, but I have enough languages prancing through my head with English, Spanish, and Hebrew.