Preheat oven to 425 degrees F. On a rimmed baking sheet, toss the potatoes with 2 tablespoons olive oil. Season with salt and black pepper. Roast for 20 minutes, or until tender. Place the salmon on a plate and rub with the oregano, paprika, orange zest, lemon zest, crushed red pepper flakes, and a pinch each of salt and pepper. Drizzle with 2 tablespoons olive oil, rubbing the seasonings evenly into each filet. Remove the potatoes from the oven and push them to one side of the pan. Put the salmon on the other side. Arrange the shallots and orange slices around the salmon. Drizzle over 1 tablespoon olive oil. Return the pan to oven and roast for 10 to 20 minutes more, until the salmon reaches desired doneness.Meanwhile, make the salsa. Combine all ingredients in a bowl and toss to combine.Toss the arugula with the remaining 1 tablespoon olive oil, the sesame seeds, and a pinch of salt. To serve, divide the salmon and potatoes between plates. Spoon the salsa over the salmon. Add a handful of arugula to each plate. Eat and enjoy!