Do you want to have the text completely removed? if so, do the following;
1 Open the "header.php" file in the "k2" folder.
2. Open the file and find;
code:
<h1><a href="<?php echo get_settings('home'); ?>/"><?php bloginfo('name'); ?></a></h1>
<p class="description"><?php bloginfo('description'); ?></p>
3. Remove that code.
You should now no longer have text on your banner.