Add a button or image button that calls wp functions in the wp-admin

I have a custom post type of products that I’ve setup to upload PDF’s using metaboxes. When I generate the metaboxes on the wp-admin, I look to see if the metabox already has a pdf uploaded to it or not. If it DOES I generate a link to the pdf. If it doesn’t I generate a file upload control where they can pick a file to upload if they want. Here’s what my function looks like that generates this metadata.

function products_pdf_uploads_show_meta() {
    global $meta_box_pdf_uploads, $post, $prefix;

    echo '<table class="form-table">';
    echo '<p class="description">Upload your PDFs here </p>';
    foreach ($meta_box_pdf_uploads['fields'] as $field) {       

        //Get current PDF meta
        $pdf_array = get_post_meta($post->ID, $field['id'], true);
        //Grab the filename from the end of the path
        $pdf_filename = substr(strrchr($pdf_array['url'], "/"), 1);

        echo '<tr>',
                '<td>';                     
                    //If Empty, show file upload dialog
                    if(empty($pdf_array)) { 
                        echo '<input type="file" style="width: 700px;" name="', $field['id'], '" id="', $field['id'], '" />';

                    } else {  //Else if pdf exists, show link to pdf and add DELETE button
                        echo '<li><a href="' . $pdf_array['url'] . '" target=_blank">'. $pdf_filename . '</a></li>';
                    }

        echo    '</td>',
             '</tr>';
    }
    echo '</table>';

What I’d like to do is if there is a PDF metadata (meaning there’s a pdf already uploaded), I’d like to put a DELETE button next to the PDF Link.

 } else {  //Else if pdf exists, show link to pdf and add DELETE button
      echo '<li><a href="' . $pdf_array['url'] . '" target=_blank">'. $pdf_filename . '</a></li>' ;
      //I Want to add a delete button after the above echo
     }

The delete button will remove all metadata from the PRODUCT post type, and delete the file off the server. SO I guess my question is how can I make a button that hooks into wordpress functions such as delete_post_meta ? I’m using wp_upload_bits() to upload the pdf’s mostly because I don’t want the PDF’s added to the media library, just want to upload them to the server and get a path.

Thanks!