1. Oil and heat grill. Sprinkle skin and cavity of each trout with salt and pepper.Make pepper salad::
2. Toss peppers with 1 tablespoon oil. Grill 6 minutes per side, until charred and tender. Wrap peppers in foil; let stand 5 minutes. Remove peel from peppers, cut into strips and toss in bowl with 1 tablespoon oil and remaining ingredients.
3. Meanwhile, grill trout 6 minutes per side, until fish turns opaque. Remove skin from each trout and discard.
4. Toss spinach with oil and lemon juice in bowl; divide between four serving plates. Arrange fish on spinach; top each trout with peppers. Makes 4 servings.