Blending Foundation’s Tabs with WordPress Nav Menu & Display Active Tab

you can write a custom class to extend Walker_Nav_Menu in your functions.php, in this class you can change all the markup

the more simple is to copy all the class from /wp-includes/nav-menu-template.php and modify what you want

class Walker_Nav_Foundation extends Walker_Nav_Menu {

   function start_lvl() // to change opening <ul>

   function end_lvl() // to change ending </ul>

   ... etc ...
}

and call it in your template

<?php wp_nav_menu( array( 'theme_location' => 'primary', 'walker' => new Walker_Nav_Foundation() ) ); ?>