The slap is easy. You strike with a totally relaxed hand and allow the fingertips only to whip onto the drum head and as quick as they strike, you pull away. Getting good fat round "tones" can take several years, but slaps are easy.

It is more difficult to get a clean slap if your drum head is not tight. If there is a lot of give when you press the middle of the head then it can stand to be pulled up (tuned) some. That will make getting a slap easier.

A teacher of mine Del Djembe, told me that getting a slap feels similar to smacking the surface of water. I think that is a very good description. Also when you are learning technique you should be careful to teach yourself good habits from the start. this helps avoid injury to your hands. If you cannot find a teacher in your area, try looking on the Rhythm Traders website for an instructional video. they have tons of dvd's and cd's. I believe it is best to learn from a teacher because you cant ask a video questions, but its a place to start.