\documentclass{article}
\usepackage{longtable}
\usepackage[RTLdocument]{bidi}
\makeatletter
\def\LT@ntabularcr{%
  \ifnum0=`{}\fi
  \LT@echunk
  \LT@start
  \hbox\bgroup\beginR\vbox\bgroup\unvbox\z@\egroup\endR\egroup 
  \LT@get@widths
  \LT@bchunk}
\def\LT@argtabularcr[#1]{%
  \ifnum0=`{}\fi
  \ifdim #1>\z@
    \unskip\@xargarraycr{#1}%
  \else
    \@yargarraycr{#1}%
  \fi
  \LT@echunk
  \LT@start
   \hbox\bgroup\beginR\vbox\bgroup\unvbox\z@\egroup\endR\egroup 
  \LT@get@widths
  \LT@bchunk}
\def\endlongtable{%
  \crcr
  \noalign{%
    \let\LT@entry\LT@entry@chop
    \xdef\LT@save@row{\LT@save@row}}%
  \LT@echunk
  \LT@start
  \hbox\bgroup\beginR\vbox\bgroup\unvbox\z@\egroup\endR\egroup
  \LT@get@widths
  \if@filesw
    {\let\LT@entry\LT@entry@write\immediate\write\@auxout{%
      \gdef\expandafter\noexpand
        \csname LT@\romannumeral\c@LT@tables\endcsname
          {\LT@save@row}}}%
  \fi
  \ifx\LT@save@row\LT@@save@row
  \else
    \LT@warn{Column \@width s have changed\MessageBreak
             in table \thetable}%
    \LT@final@warn
  \fi
  \endgraf\penalty -\LT@end@pen
  \endgroup
  \global\@mparbottom\z@
  \pagegoal\vsize
  \endgraf\penalty\z@\addvspace\LTpost
  \ifvoid\footins\else\insert\footins{}\fi}

\def\LT@rebox#1\bgroup{%
  #1\bgroup
  \hbox\bgroup\beginR\vbox\bgroup\unvbox\z@\egroup\endR\egroup
  \unskip
  \setbox\z@\lastbox}
\makeatother
\begin{document}
\begin{longtable}{|c|c|}\hline
First&Second \\ \hline
First&Second \\ \hline
First&Second \\ \hline
First&Second \\ \hline
First&Second \\ \hline
First&Second \\ \hline
First&Second \\ \hline
First&Second \\ \hline
First&Second \\ \hline
First&Second \\ \hline
First&Second \\ \hline
First&Second \\ \hline
First&Second \\ \hline
First&Second \\ \hline
First&Second \\ \hline
First&Second \\ \hline
First&Second \\ \hline
First&Second \\ \hline
First&Second \\ \hline
First&Second \\ \hline
First&Second \\ \hline
First&Second \\ \hline
First&Second \\ \hline
First&Second \\ \hline
First&Second \\ \hline
First&Second \\ \hline
First&Second \\ \hline
First&Second \\ \hline
First&Second \\ \hline
First&Second \\ \hline
First&Second \\ \hline
First&Second \\ \hline
First&Second \\ \hline
First&Second \\ \hline
First&Second \\ \hline
First&Second \\ \hline
First&Second \\ \hline
First&Second \\ \hline
First&Second \\ \hline
First&Second \\ \hline
First&Second \\ \hline
First&Second \\ \hline
First&Second \\ \hline
First&Second \\ \hline
First&Second \\ \hline
First&Second \\ \hline
First&Second \\ \hline
First&Second \\ \hline
First&Second \\ \hline
\end{longtable}
\end{document}