Preparation Rinse potatoes in a colander under cold water until water runs clear. Squeeze firmly to remove excess liquid. Transfer to a large bowl. Add salt and pepper; toss to coat. Heat 6 tablespoons oil in a large nonstick skillet over medium-high heat. Add half of potatoes; press gently into an even layer. Sprinkle with scallion whites. Top with remaining potatoes; press gently again. Cook until golden brown on bottom and sides, 10-15 minutes. Slide hash browns onto a plate. Carefully place skillet upside down over hash browns and flip to invert into skillet, browned side up. Drizzle remaining 2 tablespoons oil around sides of skillet. Cook hash browns until bottom is golden brown, 10-15 minutes longer; slide onto a plate and season with sea salt. Top with scallion greens and cut into wedges. DO AHEAD: Hash browns can be made 1 hour ahead. Place on a wire rack set inside a large rimmed baking sheet and keep them in a 200°F oven. Top with scallions before serving.
Preparation Rinse potatoes in a colander under cold water until water runs clear. Squeeze firmly to remove excess liquid. Transfer to a large bowl. Add salt and pepper; toss to coat. Heat 6 tablespoons oil in a large nonstick skillet over medium-high heat. Add half of potatoes; press gently into an even layer. Sprinkle with scallion whites. Top with remaining potatoes; press gently again. Cook until golden brown on bottom and sides, 10-15 minutes. Slide hash browns onto a plate. Carefully place skillet upside down over hash browns and flip to invert into skillet, browned side up. Drizzle remaining 2 tablespoons oil around sides of skillet. Cook hash browns until bottom is golden brown, 10-15 minutes longer; slide onto a plate and season with sea salt. Top with scallion greens and cut into wedges. DO AHEAD: Hash browns can be made 1 hour ahead. Place on a wire rack set inside a large rimmed baking sheet and keep them in a 200°F oven. Top with scallions before serving.