I've definitely wondered if they are out there. As far as ticklishness goes, if they exist, it is obviously possible as evidenced by our example, but how likely is it? It's probably very likely that they'd have some sort of tactile sensitivity, but not very likely that they'd be ticklish. Even if the idea of panspermia explained their origins and ours as one in common, or that we both independently evolved to have DNA, it would still be unlikely. For as many creatures on earth that are ticklish, most seem not to be. So, no, I don't think they would be, although I'd like them to be.