In Return of the Jedi, the ewoks plan on eating Luke, Han and Chewie.
THREEPIO: I'm rather embarrassed, General Solo, but it appears you are to be the main course at a banquet in my honor.
At this point, the tribe had already met and befriended Leia, and had encountered the Imperials in the past, making it fairly likely that they knew humans were sentient.
This raises the question of how often they ate sentients. Was it a one-off thing, to honor an extremely rare visit from a god, or was this fairly common?