If I am black, I am planning to use this Sicilian variation against my rival. So what is the system or the technique of this variation?

If you have to ask, then I have to wonder why you chose this variation. Have you played the Sicilian before? Are you prepared for all the possible anti-Sicilian lines white can play against you to avoid the line you want to play? Personally, I wouldn't dive into the Sicilian as black until I was sure I knew what I was doing, which might never happen.

--Fromper

My rival is expecting me to use the lines of Open Sicilian. So I choose the Sicilian Sveshnikov. He is not really on to Anti-Sicilians. He is much more on the main lines. The lines with d6, e6, or Nc6. My friend said this variation is for tactical players and he also said I am tactical player. He believe that this variation fits my style. I found some games using this variation and it is tactical. The problem is that I don't know the system.

If you like tactics, study tactics. So much of the value is seemingly misunderstood with regard thereto.

Practice the opening...

PC

THe sicilian is one of the trickiest openings out there - it requires a lot of study, a lot of tactical vision, fantastic defensive ability, and the willingness to look at al ot of theory.

(Lots of people think of the sicilian as a counterattacking weapon, and that's true - but onlyif you survive the first attack - and there's probably not opening that puts as much emphasis on black's ability to find only defensive moves as the sicilian.)

If you want to play any of the open sicilian variations as black, you need to first play through a bunch of master games to get a feel for what variation you want to play. (Don't play the shesnikov just because somebody said "This is tactical, you're tactical ... play it!")

Then get a good book on that variation and learn the specifics.

That's really the only way to do it. HOw much theory you need to have memorized depends on the specific variation (eg the dragon or the najdorf? Tons. The Sveshnikov? A lot less ... but still a lot.)

But the basic principles of explaining that opening are beyond the scope of a bulletin board post.

Kramnik is using Sicilian Svehsnikov. I study a lot of his Sicilian Sveshnikov games but still don't know what is the system. I know how to use the Najdorf but I won't use it to my rival because I know he is good in white when it comes of Open Sicilian. I agree that Sicilian is a counter-attacking opening. If the white just use King side pawn storm, I just Queen side expansion. Sicilian is for true fighters because it shows the bloodthirstiness of both players.

Short of buying a book explaining this variation, you can get a brief synopsis of the main lines here:
Opening theory in chess/1. e4/1...c5/2. Nf3/2...Nc6/3. d4/3...cxd4/4. Nxd4/4...Nf6/5. Nc3/5...e5 - Wikibooks, collection of open-content textbooks

Here is what my database shows as the main lines:

Sveshnikov