In terms of accessibility the best is probably La Tejita wich is a large beach parallel to the airport runway but not that close it makes it unpleasant. With a car take the road north from Los Abrigos (a lovely little port with lots of fish restaurants by the way) towards El Medano. The car park is at the far end (also the main naturist part) near to Montana Roja (Red Mountain) and from there it is a short walk to the beach. In the main part of the season there are sunbeds for hire but I'm not sure if they will be available in March. With regard to wind you should keep your eye on the weather forecast - it can often be windy but not always. Past the sunbeds, closer to the mountain is a smaller cove which is a little more sheltered.

I’ve spent a lot of time in Tenerife and think La Tejita is the one for you. My wife not naturist but she’s happy if she’s got a sun bed there. If you go beyond the rocky outcrop, you’ll find everyone is usually naturist there, but no sun beds. If you walk around the base of Montan Roja, there’s some small sandy areas with hardly a soul there. 

We will be staying at Landmar Hotel/Resort, Playa La Arena. Don't think there are any naturist beaches nearby there. Thanks Peter32 and Freebeat for responses.