Ya meng, its totally possible. I've done it a couple times.
Take out your lenses, and strap. Peel the foam off slowly and use a sharp exacto knife to slowly cut away at it. Don't pull to hard or you'll rip the foam.
Now that you have your goggles naked, use your exacto knife to slowly peel off all the paint on them. This part may take a while. Just chip off the paint.
Once there is nothing left but the rubbery goggles, take out a nice can of spray paint. I'd recomend some kind of paint that will not chip when you flex them. I can't remember the name, but go to a hobby store and they'll tell you. I picked up a nice deep red w/ gold flake.
Once that is dry, do a couple coats of enamel. You can get it in a spray can. While the first coat is sorta sticky, do the second coat. This will protect your paint job.
Get some rubber cement, not plastic cement, and lightly glue the foam back on.
Pop the lenses back in and you're good to go.
if you want to do a cheap job, just buy some enamel paint, like the stuff that comes with your model car, and paint away. It won't look as good, but it won't take as long.