I guess maybe wp_get_current_user(); is what your looking for.
Something like this…
<?php $current_user = wp_get_current_user(); ?>
<a href="http://mysite.com/mysite/page-<?php echo $current_user->ID; ?>">go this page</a>
http://codex.wordpress.org/Function_Reference/wp_get_current_user
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Actually I just re-read the question and maybe your not after the current user? You might want to elaborate the question more so we know the aim better.