Preheat your oven to 400°F and line a large baking sheet with parchment paper.
Dice the Yukon Gold potato into small, uniform cubes and toss them on the baking sheet with 0.5 tbsp of olive oil, half the sea salt, and half the black pepper.
Roast the potatoes for 20-25 minutes, flipping halfway through, until they are golden brown and crispy.
While potatoes roast, season the shrimp in a bowl with garlic powder, smoked paprika, and the remaining sea salt and black pepper.
Grill the shrimp over medium-high heat for 2-3 minutes per side until they are opaque and have developed a light char.
In a large mixing bowl, whisk together the lemon juice, the remaining 0.25 tbsp of olive oil, and finely chopped fresh parsley.
Add the arugula, roasted potatoes, and grilled shrimp to the bowl, tossing gently to coat everything in the zesty dressing before serving immediately.