Disable the “Skip to Toolbar” tabbing accessibility feature

It’s not possible without JavaScript. The HTML for it is output in the WP_Admin_Bar in a private and protected method with no filter.

You can remove them after the page has loaded with JS like so:

function wpse_287259_remove_skip_link() {
    echo "<script>jQuery( '.screen-reader-shortcut' ).remove();</script>";
}
add_action( 'wp_after_admin_bar_render', 'wpse_287259_remove_skip_link' );

I hope it goes without saying that this is something you should do just for yourself and not do for unsuspecting users who might need or want the accessibility benefits.