Remove heads from octopus by cutting below the eyes and above the tentacles and discard. Remove beak from centre of tentacles by pushing through from the cut side with your finger and discard. Combine tentacles with onion, chilli, garlic and olive oil in a bowl and set aside.
Heat a large saucepan or casserole over a low heat, add octopus mixture, cover and simmer until tender (1-1½ hours). Remove from heat and set aside to cool to room temperature.
Whisk herbs, extra-virgin olive oil, lemon juice, rind and 1 tbsp braising liquid in a bowl and season to taste.
Remove octopus from liquid (discard liquid), combine in a bowl with herb dressing, season to taste and serve with bread.