Los Cristianos. Paradise Park, they operate AI.Kids Club ect. not too far from beach. Haven't stayed myself, but reports on this site give a good reviews. Check the Tenerife hotel site, this seems to give overall views of many hotels offering your needs.
Whatever you choose, enjoy.

I have stayed in the Paradise Park and while it is an okay hotel it is a good trek from the beach especially for younger children (uphill on the way back.) I see a reference to a courtesy bus in some reviews but this was certainly not in existence when we were there. I have also just seen on a review that this is an adult only hotel unless it has changed since then?

I think they have an adults only pool at P.Park.

Try the Las Dalias/Bouganville/Torviscas playa. All good 4 stars with entertainment, pools and a sort walk to the beaches