I'm a surfer myself and although there is an annual campaign demo (
www.limmatwave.ch), there isn't actually a wave in Zurich yet.
Best bet is Bremgarten (close to Zurich) or some people do bungee surfing on the rivers as well.
Another alternative is to go wake surfing behind a boat on one of the numerous lakes. Theres also a really good river surf spot in Munich if you don't mind a couple of hours drive.
If you miss proper waves like I do, then unfortunately it will mean driving 8 hours to Hossegor.