Day time is great for eating at a beach. Shady palapas, toes in the sand.
Felipa and Beto's on the far beach to the left at Playa Estacahuite is our favorite.
Also, most of the restaurants at Playa del Panteon. We don't really have a favorite.
The one to far left, Cordelia's, is a bit more expensive, but has a more diverse menu. It's good, but we usually eat at one of the others.
You probably already know this, but if you buy at least a drink, (nicer to buy more) you can hang out at the tables or beach chairs all day.
If you want to go further, there are many restaurants on the beach in Zipolite, San Agustinillo and Mazunte, all great for day time.
Hope this helps!