In a medium size pot, drizzle about a tablespoon of the oil and heat over medium-low heat. Add the garlic and stir for about one minute then add in onion. Stir for two minutes then add in the tomato, olives, capers, anchovies, vinegar and sugar and cook for another 3 to 4 minutes. Stir in the parsley and lemon zest right before serving.
Heat a large skillet on medium heat and drizzle a little oil into the pan (at this point also coat the pan with cooking spray to further prevent sticking). Season the ʻOno with a little salt and pepper then sear in the pan for about 2 to 3 minutes per side – the trick is to not overcook the fish. Remove from the pan, place on a plate and top with a big dollop of the sauce and enjoy!