Most bounty hunter tourney's have bounties on specific players prior to the start, so you wouldn't have to worry about having a target on you (besides the obvious target of being in someone else's way of winning).
Bounty tournys need to be played just like regular tourneys. Yeah, there is some extra money out there if you knock out the right person, but don't look for that to be your income. Cash in the tourney, win it, whatever.
But the biggest mistake that people make in bounty tournament is start playing really stupid when there is a bounty at your table. If you get the chance to see it, you'll see what i mean. The person with the bounty has a target on them and people will call most anything for a random shot to knock that person out. That's also why, unless the bounty player is total donk, you will often see them with a lot of chips making it tougher to knock them out.
In a nutshell, play your normal tourney strategy. if given the opportunity to play your strategy against a bounty target, then by all means knock his ass out and collect the extra cash on the way.