by default the editor role should not have access to plugins nor appearance menu. But maybe this roles is already customised in your installation? here is a list of editor default capabilities
via functions.php you can remove everything in the appearance menu like so:
$role_object = get_role( 'editor' );
$role_object->remove_cap( 'edit_theme_options' );
to remove access to plugins you would have to remove some more capabilities i assume. update_plugins, delete_plugins and so on…
otherwise you could use a plugin to handle different roles comfortable.
i do use adminimize quite a while.