Not sure if you’re still trying to remove the Featured Image that appears on Single Posts or not, but if you want to you can do so by removing this in your functions.php file –
//* Add featured image above the entry content
add_action( 'genesis_entry_header', 'aspire_featured_photo', 5 );
function aspire_featured_photo() {
if ( is_attachment() || ! genesis_get_option( 'content_archive_thumbnail' ) )
return;
if ( is_singular() && $image = genesis_get_image( array( 'format' => 'url', 'size' => genesis_get_option( 'image_size' ) ) ) ) {
printf( '<div class="featured-image"><img src="%s" alt="%s" class="entry-image"/></div>', $image, the_title_attribute( 'echo=0' ) );
}
}