In a large bowl, combine olive oil, cumin, paprika and chili flakes. Add salmon fillets and turn to coat. Marinate for 10 minutes.
Meanwhile, in a medium bowl, stir together yogurt and lime juice. Cut cucumbers in half lengthwise, remove and discard seeds, and finely slice.
Add cucumber to yogurt mixture, along with red pepper and mint, then gently fold ingredients together. Chill until serving.
Heat grill to medium. Grill salmon for two minutes on one side, turn over, reduce heat to low, then grill for three minutes more.
At the last moment, season cucumber salad with sea salt and black pepper (the salt draws out liquid, so if added too early, salad will be a bit watery). Place a fillet on each of four plates and spoon salad on the side.
Per serving: 386 calories, 34 g protein, 22 g fat (5 g saturated fat), 13 g carbohydrates, 3 g fibre, 84 mg cholesterol, 144 mg sodium