Easily theming Form Fields - How to get minimum HTML required for form field in Drupal 7
I can't advise that you remove the labels as your website will instantly become inaccessible and fall foul of disability discrimination guidelines.

That being said, you can override the output for all form elements by implementing an override of the theme_form_element function. The easiest thing to do would be to copy that function in its entirety into a function in your site's theme called MYTHEME_form_element(&amp;$variables), and then step through the code trimming out the elements that you don't want to be output.