  Much progress has recently been made in understanding the complexity
landscape of subgraph finding problems in the CONGEST model of distributed
computing. However, so far, very few tight bounds are known in this area. For
triangle (i.e., 3-clique) listing, an optimal $\tilde{O}(n^{1/3})$-round
distributed algorithm has been constructed by Chang et al.~[SODA 2019, PODC
2019]. Recent works of Eden et al.~[DISC 2019] and of Censor-Hillel et
al.~[PODC 2020] have shown sublinear algorithms for $K_p$-listing, for each $p
\geq 4$, but still leaving a significant gap between the upper bounds and the
known lower bounds of the problem.
  In this paper, we completely close this gap. We show that for each $p \geq
4$, there is an $\tilde{O}(n^{1 - 2/p})$-round distributed algorithm that lists
all $p$-cliques $K_p$ in the communication network. Our algorithm is
\emph{optimal} up to a polylogarithmic factor, due to the $\tilde{\Omega}(n^{1
- 2/p})$-round lower bound of Fischer et al.~[SPAA 2018], which holds even in
the CONGESTED CLIQUE model. Together with the triangle-listing algorithm by
Chang et al.~[SODA 2019, PODC 2019], our result thus shows that the round
complexity of $K_p$-listing, for all $p$, is the same in both the CONGEST and
CONGESTED CLIQUE models, at $\tilde{\Theta}(n^{1 - 2/p})$ rounds.
  For $p=4$, our result additionally matches the $\tilde{\Omega}(n^{1/2})$
lower bound for $K_4$-\emph{detection} by Czumaj and Konrad [DISC 2018],
implying that the round complexities for detection and listing of $K_4$ are
equivalent in the CONGEST model.
