I personally know several Artists in my hometown that are not shy about their drug use specially hallucinogenics, and a few of them told me that they use hallucinogenics to open their minds and to get another perspective of reality.

One of them even told me that DMT is like food for his brain that every time he takes a breakthrough dose his Art gets better and I agree with him 100%.

So I wouldn't be surprise if Dali knew and use this tools as well.

I've been to the Dali museum in Figueres, ( Catalonia region of Spain) it's full of trippy artwork and interesting instalations he did.( Even the building itself is trippy) To me there's a definite LSD flavour to most of the surrealists work. A bit creepy and stuffy for my taste. ( the jewelery range he did, are also very interesting) I beleive that he did acid, but if it influenced the origins or even the entire direction of his work is anybodys guess.

I doubt very much if he tried DMT, though I could imagine how his work would have looked populated with aliens and clever friendly entities pouring out of UFO's!