To poach fish: Preheat oven to 325°F. Combine water, bay leaf, salt and pepper in a 2-quart baking dish. Add fillets skin side up and bake 15 minutes, until just cooked through. Let fish stand for 5 minutes more before removing with a slotted spoon. Set aside to cool to room temperature.To make salad and dressing: Turn oven up to 400°F. In a small glass baking dish, toss mushroom caps with vinegar, salt and pepper to taste. Roast for 10 minutes, until softened and browned. Set aside to cool to room temperature.In a large bowl combine 3 1/2 cups spinach, diced tomatoes, green beans, endive, olives and capers. In a small bowl, slowly whisk oil into lemon juice until slightly thickened. Season to taste with salt and pepper before tossing into vegetables.To serve, divide greens onto four plates, top each with a salmon filet, and sprinkle with parsley.