A suspended cymbal is exactly what it is called. It is a cymbal that is suspended from something. If you are a drum set player, you have a suspended cymbal, or maybe a couple of them, already on your drum set. You call them crash cymbals. They range in size from 15" to 20", possibly bigger or smaller, and every size in between. That's a lot of cymbals. For most applications, you can get away with two sizes: 16" or 17", and 18" or 19". You also want them fairly thin so they will develop a nice "bloom" to the sound when you play them.
Some pros like to use a cymbal that is suspended from a hook by a leather strap, the same kind of leather strap that you would use with a set of orchestral crash cymbals. Yes, it does give you the best sound, but for most of us, it's not practical. Cymbal hooks are not cheap. When I was in the Air Force Band, we had cymbal hooks that were made by an iron works company.
A good quality crash cymbal mounted on a regular cymbal stand will work just fine. Make sure that the cymbal is completely horizontal, and you play it at about waist level. Ideally, you should have a variety of cymbals for this purpose. They should range from paper thin to about a medium thin thickness. The brand is your choice. Many swear by Zildjian. Many swear by Sabian. Many swear by Paiste. Some prefer Crescent, Istanbul, or Bosporus. Cymbals, like triangles, are highly personal.
So what do you use to strike the cymbal? What you use, depends on the requirements of the music. First of all, don't use timpani mallets unless you need to because you are covering a tom tom part at the same time. What you would normally use are the same mallets that you would use on a marimba or vibes. Occasionally, you would use a regular drum stick. I like to use a nylon tip stick. If called for by the composer, use a triangle beater. I've actually scraped a suspended cymbal with a coin when the composer called for it.
One thing that I've noticed when I'm teaching a beginning percussion student how to play a roll with mallets on a suspended cymbal, is they can not get a smooth sound. The trick is to keep yourself very relaxed and use a loose grip. Also, play on the edge rather than half way up the cymbal. For some reason, most beginning students have a hard time keeping the right mallet at the right edge of the cymbal, and the left mallet at the left edge of the cymbal. They all want to keep the mallets next to each other right in front of them. Use the mallets to play a sustained roll, and then if you have to decrescendo, use less energy in your roll to minimize the vibrations of the cymbal. Another thing that I find amusing, is they want to lower the cymbal stand so that they can sit and play the cymbal. They do the same thing with snare drum. What this tells me, is that most students today, are not given proper exposure to the various percussion instruments. All they know is drum set.
Gone are the days when you stood in front of your teacher at a snare drum, and that teacher micro-managed every detail of your stroke, until it became second nature. While I don't want for the good ol' days, I do think that there needs to be a little more emphasis on proper technique. The result of not having good technique is worse than the hard drills required to achieve that technique. The better your technique, the better you can play, and the easier time you will have learning your music.