No way to assign custom id for the table in the current release, but in the next release we've added a predictable table id which you can use. It'll be
$md5_id = md5($this->get_path());
$theme->assign('table_id','table_'.$md5_id);
However currently you can assign a custom attributes to the rows
$row = $gb->get_new_row();
$row->set_attrs(' style="..." onclick=".." etc ');
and even to the cell with
$cell1 = array('value' => 'Test', 'attrs' => ' ... ');
$cell2 = array('value' => 'Test', 'attrs' => ' ... ');
$cells = array($cell1, $cell2);
$row->add_data_array($cells);
Regards,
Adam
