Napoleon Dynamite was a strange cultural phenomenon that somehow had the right amount of weirdness at the right time. I can't really explain why I find the movie so funny, it's not even Jon Heder's character in the film, or Pedro's sullen, understated expressions. It isn't even Napoleon's dance or Uncle Rico's lameness. I think what makes it so great is all of that strangeness coalescing into one unforgettable film.
And although the movie's packed with tons of memorable scenes (my personal favorite is Uncle Rico decking Napoleon in the face with a steak, not his own steak, mind you) it's hard to argue against Napoleon's pocket tater-tots as being at the top of the pack.
So Burger King is selling some cheesy tater tots (that are probably gross, let's be honest here) and thought that the best way to promo them would be to get Napoleon and Pedro back together on camera for some lunch.