Hi Linxie,
Be careful with the paella as it is often made with FIsh Stock. Salads always have tuna or ham so make sure you make the point very clear: Ensalada solo verdura
The word for vegan is VEGANO/a as you said but not very many people at all know the meaning. If your spanish is ok, you are better off explaining, otherwise I strongly recommend a vegan passport or checking happycow.net
Best of luck!