Translation:No, we do not have any warm potato salad.
Nowhere. It is usual to put it there in English, but the sentence is accepted without it as well.
I believe you could use "žádný" to make that "any" explicit (the Czech sentence would be "Ne, teplý bramborový salát žádný nemáme"). Also (as far as I know), "žádný" can only be used in negative sentences.
Yes, Pedro. But in that case, a different word order is more common: "Ne, žádný teplý bramborový salát nemáme".
Thanks for the reply! I've heard that word order in Czech is more flexible because the cases (pády) already communicate the relationships between words, but (as you said) certain orders are more common. In this case, since "žádný" ends in "-ý", I guess it is an adjective that qualifies "teplý bramborový salát", and that's why it should come before it (because adjectives usually come before of what they qualify).
Added, please do use "My answer should have been accepted". It is extremely easy to miss a valid form when we don't have the reports at hand.