The Charlatan
Welles opens the film with a magic trick. He takes a key from a young boy and turns it into a coin. It's a trick that he as a child saw Houdini perform. Welles is asking us to trust him and in the same breath tells us this film is about lies. He, himself becomes the sybols for trickery throughout the film. He even hides this symbol in plain sight when at the beginning he tells the woman on the train that he is a charlatan.
Wine Spilled on the Map
As Welles begins to explain the beginning of this story he uses a map to point out Ibiza, the location of the two men he wants to explore. Just before points it out, Welles spills his glass of wine on the map. It symbolizes that Welles himself is making the water murky, and while he is asking us to trust him to tell the truth. He's someone we don't really know.
Burning the Fakes
We see Elmyr burning the fake paintings that he has recreated. It symbolizes his disregard for the money he could make for what the "experts" would deem an authentic masterpiece. The dual symbol is also his arrogance, that he can create another masterpiece while no one is looking, and burning a painting is all for show. To create an identity for others to believe about him.
Welles' Black Cape
Orson Welles is seen dressed in a black hat and black cape for the majority of the film. Many times he appears to be out of place to those around him. His all black dress is a symbol for him being the magician of this film. He is the narrator, and thus controlling the story, and most importantly controlling the truth.
Monkey of Irving
Throughout the film we see a small monkey sitting on Irving's shoulder. It comes to be a symbol for the monkey that Irving appears to have on his back about Emyr. The weight of exposing Emyr is so heavy on him that he wears it like a companion he tries his best not to notice. And, when you watch Irving, he hardly acknowledges the animal. Similar to his own reasons for why he's after Emyr at all.