Preheat your oven to 400°F and line a large rimmed baking sheet with parchment paper.
Wash the russet potato thoroughly and slice it into thin wedges or half-inch cubes to ensure they become crispy.
In a medium bowl, toss the potato pieces with half of the olive oil, a pinch of sea salt, and a pinch of black pepper.
Spread the potatoes in a single layer on the baking sheet and roast for 15 minutes.
While the potatoes are roasting, pat the salmon fillet dry with a paper towel and rub with the remaining olive oil and lemon juice.
Season the salmon evenly with the dried oregano, garlic powder, and the remaining sea salt and black pepper.
Carefully remove the baking sheet from the oven, move the potatoes to one side, and place the salmon fillet on the other side.
Return the tray to the oven and roast for an additional 12 to 15 minutes until the salmon is opaque and flakes easily with a fork.
Garnish the entire dish with freshly chopped parsley and serve immediately while the potatoes are hot and crunchy.