Ok, I got the point (and your PM).
The wildest area in Sardinia is the West Coast. There is an area called Piscinas, where you have to drive 1-2 hours to go down there. It is south of Oristano, a huge wild beach with sourrounded by Mediterranean vegetation and dunes. But, there is always a but....
There are a lot of mosquitos, which pissed me off and the sand is not that beautiful compared to many other beaches.
I can not say anything about wind, when I was there there was no wind at all, but it may come as thermal and the whole West Coast is open to Mistral (Maestrale), which blows you away.
Going south, reaching the south west tip, you will found also Porto Pino, white big sand dunes and blue waters, almost wild.
Going to the north part, I suggest you la Costa delle Rose, between Porto Torres and S. Teresa. It is a very large costal area with beaches and rocks, quite wild.
A bit northward from Oristano you can also stop in Putzu Iddu (or Capo Mannu) where you get beautiful beaches and,if Maestrale blows, you can get maybe the best wave spot in the Mediterranean Sea.
Anyway the whole West Coast is really beautiful and less turistic: Bosa (no kiting here), Torre Argentina (no kiting here), Alghero, Torre dei Corsari (no kiting here) are fantastic.
Remember that free camping is usually not allowed (sometimes tollerated), and it might be also dangerous.