Not a few minutes into Jesse Eisenberg’s post-screening Q&A for his latest film, “Sasquatch Sunset,” I attempted to reformulate the old saw about how children should be seen and not heard. Might the same be said for movie stars? The loquacious Mr. Eisenberg — buzzing, I think, on too many cups of coffee — spoke at length about the picture’s technical issues, predominantly the challenges of acting while wearing prosthetics. An artist talking about his craft: interesting.