Preheat oven to 200°C. Line an oven tray with baking paper.
Combine all baked rice ingredients in deep, oven-proof dish. Mix well and cover dish with foil, making sure to seal the edges well. Bake for 25 minutes, then remove from oven and set aside.
While rice is cooking, pat salmon dry and remove any remaining scales or pin bones. Season salmon and place, skin-side-up, to one side of prepared tray. Add diced bread to other side of tray, drizzle with olive oil and season. Bake (on rack above rice) for about 12 minutes, until salmon is cooked through.
While rice and salmon are baking, add remaining red onion and semi-fried tomato to a large bowl and set aside.
When salmon has finished cooking, set aside to rest for at least 5 minutes. Carefully peel skin off salmon then break into large chunks using a fork. Add to bowl with onion and tomatoes. In a small bowl, combine mayonnaise and lemon juice and set aside.
Fluff up rice with a fork. Add mesclun, baked ciabatta and vinegar to bowl with salmon and gently toss to combine. Season to taste.
To serve: spoon baked rice onto plates and top with flaked salmon salad. Drizzle with lemon mayonnaise.