How to get user meta from custom table?

Yes! That worked, thank you 🙂

Is there a function to retrieve all metabox fields, from a custom table? (in this case for a User, but I was wondering about posts as well)

Excellent, thank you.
Some users may be interested in my little function:

function mb_customtable_getRow($object_id, $table_name){
    $ra =  MB_Custom_Table_Cache::get( $object_id, $table_name );   
    foreach($ra as $k=>$v){
        $newra[$k] = maybe_unserialize( $v );//this is a wp func.
    }
    return $newra;
}