As you can see from the photos above, Playa de los Cuervitos (pebbles) and Playa de los Tres Peos (golden sand) are two small beaches side by side in the same cove. The volcanic rock that runs out into the ocean seperates them; it also prevents the pebbles from los Cuervitos and neighbouring Playa de las Cruces from reaching Playa de los Tres Peos.
The rock formation forms a kind of barrier preventing the strong waves along this part of the coastline from smashing into the beach. It's very easy getting in and out of the water, so much so that a dog would be safe splashing around in the water here. Ah I should mention, these are one of two areas on the island where dogs are officially allowed to play. You'll probably see dogs on beaches all over the island but the police could pull up the owners elsewhere and fine them from between 500 to 5000 euros. Not here, they are allowed on both of these beaches.
This is a very windy part of the island, just a few meters away are the kite surfers and past them the wind surfers. Playa de los Tres Peos is usually very quite because if this and it also means you should be able to find a protected part to the side. When I went down (that's me in the photos with my Doberman and a friend) there was a small group of friends and they obviously had no problem with the dogs playing there. If you don't like dogs, avoid this beach.
Getting there take exit 25 off the GC1 motorway then head north on the GC-191 to the roundabout with the windsurf boards on it and follow the sign (right/first exit) for Vargas. Keep straight along this road to the end and you'll first arrive at Playa Vargas. You want to go right and as far as you dare with the car then park and carry along on foot to the hill at the end. These beaches are just over that hill.
There's even a camping as you arrive at Vargas where you can grab something to eat and drink.