Interview with George Takei is here:
Here's an excerpt:
Q: It’s hard to represent Asia since it goes all the way from Pakistan and India to South Korea and Japan.
Takei: And the name Kim is specifically Korean. Wong is Chinese. Tanaka is Japanese. So he was trying to find something that would suggest all of that part of the map. And so he found to the west of the Philippines a sea called the Sulu Sea. And he thought, ah, the waters of the sea touch all shores, and that’s how he came up with the name Sulu. And he said that this character would be a full-fledged professional, the brightest guy out of Star Fleet academy, a very good helmsman, eventually to become the best helmsman of the Star Fleet, and he would be part of this leadership team of the Enterprise. I was excited.
Because I’d been playing the stereotyped Asian roles. I desperately wanted that part.