Nope. They are not typically used in salt water setups, unless you really like to get salt creep everywhere. If you have enough circulation with powerheads, etc, then you should be fine.
Your skimmer will produce enough oxygen bubbles while skimming. I use to run a power head with the air line tub hooked up and I would oxygenate it every now and then but the bubbles that the skimmer makes is enough. Plus air bubbles in a reef is bad.
Your skimmer should do all the work for you. The only reason you would need one is if you get too much salt creep. Air bubbles in a reef isn't really good either.