Heat a grill pan or outdoor grill over high heat.
Drizzle extra-virgin olive oil over the fish and season with salt and pepper. Grill 4 minutes on each side until fish is firm but not tough and cooked through. Grill bread alongside or char under broiler then dress with extra-virgin olive oil, salt and pepper as well.
Preheat a skillet over medium-high heat.
While fish cooks, peel the orange as you would a melon: cut off ends, stand it upright and cut off skin and pith in thin strips from top to bottom. Cut orange across into thin slices.
To preheated skillet add extra-virgin olive oil, 2 turns of the pan, the fennel and onions, season with salt and pepper and cook 3 to 5 minutes until seared and beginning to soften. Add vinegar to the pan and give it a shake. Remove from heat and toss in the oranges, the parsley and oregano. Adjust seasoning and serve salad on dinner plates topped with fish, and seasoned bread alongside.