Is there a Naruto or One Piece crossover manga or anime? Have both of the authors collaborated in anyway?
Kishi and Oda make reference to each others works from time to time.
For example, One Piece made a reference to Naruto in chapter (766):. Nami's dress with has symbol on it, and how there's a fox eating ramen with a whirlpool on its back. Kishi also put a One Piece skull and crossbones (along with the straw hat) on the very last page of the last chapter of Naruto.
Although there are no offical crossovers, there are many fanfics about this.
At this point there is no "official" collaboration in the anime or outside between this two, but a special collaboration was made by MAG Project (Manga-Anime Guardians Project).
With the purpose of being publicity for anime and manga, “Join Us, Friends” essentially creates a bridge and brings together publishers and anime companies that compete in the marketplace with each other. As a symbol of this, this special illustration crosses over works to bring together popular characters from five series: One Piece, Naruto, Sword Art Online, Detective Conan, and Attack on Titan.
No, I have not come across any.
There is a special episode on Toriko that features Luffy (One Piece), Goku (Dragon Ball) and Toriko, but not Naruto characters.