In this paper, we show that the boundary $partial Sigma (W,S)$ of a right-angled Coxeter system $(W,S)$ is minimal if and only if $W_{tilde {S}}$ is irreducible, where $W_{tilde {S}}$ is the minimum parabolic subgroup of finite index in $W$. We also provide several applications and remarks. In particular, we show that for a right-angled Coxeter system $(W,S)$, the set ${w^{infty }|win W, o(w)=infty }$ is dense in the boundary $partial Sigma (W,S)$. [ABSTRACT FROM AUTHOR]