Preheat oven to 400 degrees F. Lightly spray a baking sheet with olive oil cooking spray; set aside. In a microwave-safe bowl, combine 1 1/2 cups fresh or frozen corn kernels, 1 (4.5-ounce) jar sliced mushrooms, 2 tbsp chopped pimentos, 1/2 tsp crushed garlic, 1 tbsp chopped fresh flat-leaf parsley, 1 tsp herbs de Provence, and 1 tbsp balsamic vinegar. Mix thoroughly and set aside. Cut salmon into 4 serving portions. Use a pastry brush to brush salmon with olive oil. Coat salmon with herbs de Provence and place fillets on prepared baking sheet. Bake in preheated oven for 15 to 20 minutes. Cover corn mixture and heat in microwave on HIGH for 2 to 2 1/2 minutes. Serve salmon immediately over corn mixture.