How can I set up a splash page that is redirected to only one time for the visitor? [closed]

Adding a splash page adds an extra step between your user and the information they are looking for. Making it non-optional as you seem to be suggesting will have a serious impact upon your visitor figures. Personally I would not want to impart my email address to a website without knowing more about the site and if it even has the relevant information I am looking for. I would strongly suggest you make this an optional pop-up.

Now to answer your question. To achieve this you would need a plugin, you can either write your own or use a pre-built one. I personally would write my own as I could tailor it to my own needs.

As others have suggested cookies are the best way to achieve this. If you do use cookies you will need to display a warning message to visitors from the EU that you are storing a cookie on their computer.