Coat a large saucepan with olive oil.

Add the onions to the saucepan and cook over medium heat.

Season with salt and crushed red pepper.

Cook for 5-7 minutes, until onions are softened but not browned.

Add the garlic and cook for another 2-3 minutes, until fragrant.

Stir in the tomatoes and 3/4 can of water and salt.

Bring the mixture to a boil, then reduce to a simmer and cook for 20-30 minutes.

Taste and adjust seasoning as needed.

Bring a pot of water to a boil and season generously with salt.

Add the cauliflower and cook for 5-7 minutes, until very soft.

Strain the cauliflower and add it to the tomato mixture.

Cook until the cauliflower breaks down and the sauce clings to it, about 20-30 minutes.

Adjust the seasoning.

Stir in the lemon zest, olives, and caperberries.

Reserve the cauliflower mixture.

Preheat the grill to medium and brush with oil.

Pat the fish skin dry.

Drizzle the fish with olive oil and season with salt on both sides.

Place the fish skin-side down on the preheated grill.

Cook for 2-3 minutes, then rotate 90 degrees to create grill marks.

Cook for another 2-3 minutes, then turn the fish over and cook for another 2 minutes.

Reheat the cauliflower mixture if needed.

Serve the fish on plates, leaning on a mound of the cauliflower.

In a small bowl, toss the parsley with the lemon juice, salt, and olive oil.

Garnish the fish with the parsley salad and additional olive oil, if desired.