Well, it's actually quite bad English to call a map a "hunter". I know people do it. I even do it sometimes.
A map that has a route in which you can hunt a good time is usually one where lots of spots afford the opportunity to gain little bits of time all over the place. That's when things get interesting and you can have some nice battles with the best times between really good drivers as they try to beat each other. Or perhaps you're just trying to beat your own record on the track and you feel like you gain a little more time on every run. To me, that's a "hunter".
The style of track doesn't matter so much as the player who is playing it and whether the map engages him to the point where he wants to continue improving his time.
I recently hunted a time on an offroad map by expack. The time I hunted was actually using a cut... taking the CPs out of order.. but I drove it for 30+ minutes looking for the best route and trying to take it as smoothly and quickly as possible.
Here's the video of my final run:
http://www.youtube.com/watch?v=9jsBoyqAV4w
As you can tell, it's not the ordinary type of speedtech map you'd expect someone to hunt. But I had fun improving my time on it nonetheless.