According to the docs
Using the third argument Router::connect(), you can determine which route elements should also be available as passed arguments:
Router::connect('/jobs/:slug',array('controller'=>'jobs','action'=>'index'), array('pass' => array('slug')));
and, in your opinion, you can create a link using
echo $this->Html->link('link', array(
'controller' => 'jobs',
'action' => 'index',
'slug' => 'your_slug'
));