In the food court before Security you'll find a few Japanese eateries including sushi and noodle bars, a Western-style restaurant, a couple of café-bars, and a burger counter. There's only one café after Passport Control.
If you're departing from Terminal 3, and arriving by train or car, you'll need to park up at Terminal 2 first, or come into the Airport Terminal 2 Station.
The walk from there to Terminal 3 is about 15 minutes, or you can wait for the direct shuttle bus which takes about 5 minutes.