\documentclass[]{beamer}
\usepackage{geometry}
\geometry{landscape,a5paper,left=1mm,right=16mm,top=1mm,bottom=0cm}
\usepackage{tcolorbox}
\tcbuselibrary{skins,hooks}
\usepackage{tikz}
\usetikzlibrary{intersections,spy,matrix}
\begin{document}
\begin{tcolorbox}[enhanced,arc=0.5mm,boxrule=0.5mm,frame hidden,colback=blue!4,borderline={0.5pt}{0mm}{black,dashed},left=0.25mm,right=0.25mm,top=0.25mm,bottom=0.25mm]
\begin{figure}[h!]% H h! h - тут; t - вверху страницы; b - внизу страницы
\center\begin{tikzpicture}[scale=0.2]
\filldraw [fill=red!50, draw=gray] plot[smooth] (35,0)--(85,1)--(90,40)--(120,35)--(115,20)--(70,30)--(14,1);
\end{tikzpicture}
\caption{Picture picture}
\end{figure}
\end{tcolorbox}
\end{document}