\documentclass{biditufte-book}
\usepackage{multicol}
\usepackage{ptext}
\usepackage{xcolor}
\usepackage{xepersian}
\settextfont{Yas}
\makeatletter
\newenvironment{wider}
               {\list{}{\leftmargin\z@\relax
                        \rightmargin-\@bidituftefloat@overhang\relax}%
               \item\relax}
               {\endlist}

\def\foo#1\moveright#2\full@width#3#4\foo{%
\def\page@sofar{%
#1%
\dimen@\multicol@leftmargin
\ifodd\c@page\else\advance\dimen@\@bidituftefloat@overhang\relax\fi
\moveright\dimen@
\hbox to \full@width{%
     {\color{lightgray}\vrule \@width \full@width}%
     \kern-\full@width
#3}%
#4}}
\expandafter\foo\page@sofar\foo
\makeatother


\begin{document}
\ptext[1]

\begin{wider}
\begin{multicols}{2}
\ptext[1-15]
\end{multicols}
\end{wider}

\ptext[1-3]

\begin{wider}
\begin{multicols}{2}
\ptext[1-100]
\end{multicols}
\end{wider}

\end{document}