Preheat the oven to 375˚. Combine the bread cubes, olives, red onion and cherry tomatoes on a baking sheet. Sprinkle with ½ teaspoon salt and a few grinds of pepper and drizzle with 2 tablespoons olive oil. Toss until everything is evenly coated. Bake until the bread just starts to crisp, 12 to 15 minutes. Rub the salmon with 1 tablespoon olive oil and sprinkle with ½ teaspoon salt. Arrange on the baking sheet among the bread mixture. Bake until the salmon is opaque and flakes easily with a fork, 8 to 12 minutes. Meanwhile, whisk the remaining 1 tablespoon olive oil with the vinegar in a large bowl. Add the capers. Arrange the salmon on a platter and top with chopped parsley. Add the bread mixture to the vinaigrette along with the parsley leaves. Toss until completely coated. Serve the salmon with the bread salad.