Place freekeh and 1 1/3 cups boiling water in a large heatproof bowl. Microwave, uncovered, on high for 14 minutes or until just tender. Stand, covered, for 10 minutes or until liquid is absorbed. Stir with a fork to separate grains. Set aside to cool completely.
Combine chia seeds and cumin on a large plate. Season with pepper. Coat top and bottom of salmon with chia mixture. Spray a large non-stick frying pan with oil and place over medium heat. Cook salmon for 4 minutes on each side for medium or until cooked to your liking.
To make lemon, garlic and herb dressing, combine zest, juice, garlic and mint in a small glass jug or bowl. Add oil and whisk with a fork until combined. Season with pepper. Place freekeh, tomato, onion, parsley and mint in a large bowl. Add dressing and toss to combine. Season with pepper. Divide freekeh tabouli among plates. Serve topped with cucumber and salmon.