The simplest method is not use $POST, and to use $GET instead.
So your link will be <a href="page.php?var=Hello">, and in the new script, page.php, there'll be a variable called $_GET['var'] that will contain "Hello".
It is possible to make a form that contains a hidden variable, and then use an anchor element (<a href>) and javascript to submit the form, that'd pass it via POST, but its mucho hassle.