No. Cyprus is not part of the Schengen Area. A Schengen visa is not valid in Cyprus.
You need to apply to the Spanish Embassy in Vietnam. A Schengen visa is a visa that allows you to go to all the countries in the Schengen Area. Once you are legally in the Schengen Area, you can freely travel to any other Schengen country.
If you've already had a Schengen Visa then go to an European coutry signed the Schengen Agreement, of course you could go to other Schengen countries.
Yes, you need a separate visa for Ireland. Ireland is not part of the Schengen Area. Schengen visas are not valid.
Cyprus is not part of the Schengen Area. A Schengen visa is not valid in Cyprus.
Ireland is not part of the Schengen Area. Schengen visas are not valid.
If you have a Schengen Visa, you do not need a Visa to enter Switzerland. But, just make sure that you have this written "Schengen Estate" on the visa. It means that all Schengen countries are included in the visa. Anyway, once you enter Europe, nobody asks you about your visa or passport.
Yes, Switzerland is part of the Schengen Area. Schengen visas are valid.
If you need a Schengen Visa it applies for all Schengen countries, this means that you can then travel freely within the Schengen area for the length of your visa.
Yes.If you need a Schengen Visa it applies for all Schengen countries, this means that you can then travel freely within the Schengen area as long as your visa remains valid.
Ukraine is not part of the Schengen Area. A Schengen visa is not valid in the Ukraine.
No, a Schengen visa is not valid for Istanbul. Istanbul is in Turkey, and Turkey is not part of the Schengen Area.