The peruvian coast is a desert. Lima is the capital and most of the beaches in its coast are urbanized. I like the beaches with a natural coastline with cliffs and desert. There are still a few of them, but the access is not easy. It is necessary a off road truck.
My favorite beaches are in Punta Salinas, which is in the north of Lima (about 2 hours). The water is cold and it is often windy, but i love the desert and walk on the sand.
Tartacay
Chocán