Most fish require a short cooking time, but cephalopods are the exception to this fishy rule. As with some cuts of larger land beasts, the longer they're cooked, the more tender they get.
My father always cooks more polenta than he needs for a meal. The excess he spreads on an oiled surface and chills. Next day, he cuts out chunks, fries them in olive oil and serves with salad.
Yoghurt cuts sweetness and richness, tempers spice, and makes a dish sing.