1. Heat the oil in a large saucepan over medium-high. Add the leek and fennel and cook, stirring occasionally until lightly browned, 4 to 5 minutes. Add the garlic, salt, and turmeric and cook, stirring, 1 minute. Add the broth and bring to a boil.
2. Add the couscous; reduce heat to medium-low and simmer, 5 minutes. Add the salmon and tomatoes and cook, stirring gently, until the salmon is cooked through, 8 to 10 minutes. Break the salmon into pieces and serve the soup topped with the dill.