Preheat oven to 375°F (or preheat the grill to medium high).
Brush each piece of salmon with 2 tsp (10 ml) olive oil, and season with salt and pepper to taste.
Place each fillet on an individual sheet of tinfoil large enough to encase the fish. Top each salmon piece with a sprig of thyme, slice of lemon and 1/2 teaspoon (2 ml) of capers. Fold sides of foil up to fully seal the fish package. Place on a baking sheet and put in oven or on grill. Cook 15 minutes.
Meanwhile, add the remaining 1/4 cup (60 ml) olive oil plus onion and fennel to a sauté pan and cook over medium heat for five minutes. Add spinach, fold together and heat through just to wilt spinach, then season and divide among four plates. Top with salmon and 'contents of foil package, including liquid.
Per serving: 415 calories, 28 g protein, 29 g fat (5 g saturated fat), 16 g carbohydrates, 8 g fibre, 47 mg cholesterol, 382 mg sodium