As they said, "Ethnicity doesn't affect sensitivity". What's more, there isn't any way to compare "ticklishness" between two regions, because it's some absolutely random characteristic from each women. And there aren't any value to rate ticklishness so even a statistic would be useless, there aren't any realistic answer to that question.
But there is one "virtual" answer, and it's because even if ethnicity doesn't affect directly in ticklishness, it can affect in some kind of attitudes that can be reflected in the reactions. What I'm tryng to say with my awful english limitations, is that even if a ethnicity isn't more or less ticklish from the other, maybe one can react more loudly to tickling, what can be confunded with being more ticklish. And, in my opinion, this happen with Latina women, I think the Asian are a little quiter.