This one is a bit harder since it involves timing, but to do the airborne windbomb, paraglide for a short distance, drop a bomb, a enter bullet-time (when you pull out your bow in mid air), make sure you DON'T draw your bow, just pull it out by tapping ZR, drop the other bomb, wait until the bombs and Link are lined up and detonate the first bomb.
To do the grounded windbomb, sprint and jump off the side of something (cliff, rock, etc, as long as you can enter bullet time off it) drop one bomb, enter bullet time, drop the other, wait until everything is lined up at the angle you want to go and detonate the first bomb.