You would need to modify them on the theme files The polls menu can be turned off if you disable the polls altogether. Otherwise if you still want polls, you could edit the file /components/com_easysocial/themes/wireframe/toolbar/default.php and remove the codes below,

[gist]
<?php if ($this->config->get('polls.enabled')) { ?>
<li class="<?php echo $view == 'polls' ? 'is-active' : '';?>">
<a href="<?php echo ESR::polls();?>" class="es-navbar__footer-link">
<i class="fa fa-bar-chart"></i>
<span>
<?php echo JText::_('COM_EASYSOCIAL_TOOLBAR_POLLS');?>
</span>
</a>
</li>
<?php } ?>
[/gist]