Prepare the salmon:
Preheat oven to 200º C and line a baking tray with non-stick baking paper. Make two to three incisions across each piece of salmon and rub in the mustard then sprinkle with lemon juice. Place the salmon, skin side up, onto the baking tray and add the tomatoes. Season salmon and tomatoes with salt and pepper and drizzle with 1 tablespoon of olive oil.
Bake for 15-18 minutes until salmon is cooked and tomatoes have collapsed. Remove from the oven, cool and flake the salmon into chunks with or without the skin.
Prepare the condiments:
Heat remaining olive oil in a large frying pan and sauté onion until lightly browned. Stir in the garlic and mustard seeds and cook for 1-2 minutes. Add the fennel and cook for 4-5 minutes until soft, then stir in the mustard.
Prepare the quinoa:
Stir in the dill, quinoa and water and season with salt and pepper. Bring to the boil, reduce the heat, cover and simmer for about 15 minutes until the quinoa is cooked and all the liquid is absorbed.
Gently toss the salmon and tomatoes through the quinoa, squeeze a good amount of lemon juice over the top and garnish with extra chopped dill.