  The notion of dynamically convex has been studied since it was introduced by
Hofer, Wysocki and Zehnder. In particular, they showed that there muse exist a
global surface of section of disk type binding a periodic orbit for the Reeb
vector field in dynamically convex $(S^{3},\lambda)$ by using pseudoholomorphic
curves. Recently Hryniewicz and Salom\~ao showed the same result for $L(2,1)$
by developing the original technique and after that Schneider generalized it to
$(L(p,1),\xi_{\mathrm{std}})$. The main purpose of this paper is to introduce
an alternative approach of using Embedded contact homology. In particular, we
find a global surface of section of disk type in dynamically convex
$(L(p,p-1),\xi_{\mathrm{std}})$ and relate their periods to the first ECH
spectrum.
