In a small bowl, combine sauce ingredients, plus a pinch each of salt and pepper. Brush all over fish. Place fish on a greased grill over medium-high heat; close lid and grill, turning once, until fish flakes in centre, 8 to 10 minutes.
Meanwhile, in a large bowl, whisk 2 tsp (10 mL) olive oil with yogurt and vinegar, plus a pinch each of salt and pepper. Fold in cucumber, red pepper, green onion and mint, and stir until coated.
Serve fish with salad and, if desired, some kalamata olives and grilled whole-grain sourdough bread.
Serves four. Per serving: 181 calories, 27 g protein, 6 g fat (1 g saturated fat), 5 g carbohydrates, 1 g fibre, 54 mg cholesterol, 118 mg sodium