Some Restaurants:

La Pizzeria de Guia - in Guia de Isora - Italian 

El Rincon de la Barriga - in Alcala - Tapas, Fish

Sauco - in Alcala - Fish and Italien inspired - nice location at the sea front

Bar Arepera kilometro 101 - in Santiago del Teide - South American, not very cozy but great Arepas

Tasca 1900 - in Guía de Isora - original canarien restaurant

Quinta Esencia - in Playa San Juan Close to the sea - Italian inspired. A bit more expensive but good quality.

La Nonna - in Chio - good Italian restaurant - no pizza! Always busy - make a reservation.