I think part of this could be boredom eating, and part of it could be habitual eating.
For the habitual eating (such as munching while watching TV), you may just need to make a point to try to break the habit. Two of my worst sources of habitual eating used to be while watching TV and on car trips--I just had to decide to stop.
Boredom eating is a more difficult issue, for me, anyway. While I'm better now at fighting the munchies when not hungry, the mild hunger pangs are definitely more problematic when I'm at home not doing much (I can usually ignore them when I'm busy at work). One thing that helps me is Crystal Light On-The-Go. It's tasty and reasonably filling, and only 10 calories per tube.