Combine water, kosher salt, and baking soda in a pot over high heat and bring to boil. Add potatoes, simmer, and cook until barely tender for 10-12 minutes. Drain and let sit for 30 seconds.

Whisk olive oil, garlic powder, onion powder, paprika, and black pepper in a mixing bowl.

Transfer the potatoes into the bowl of seasoned oil and coat evenly, roughening up the surface slightly.

Preheat the oven to 450°F. Line a baking sheet with parchment paper.

Spread potatoes on the prepared baking sheet, smear mashed bits on top, and season with a pinch of salt.

Roast potatoes at 450°F for 45-60 minutes, turning them over every 15-20 minutes until crispy and browned.

Heat olive oil in a skillet over medium heat. Add onions, peppers, and salt, cooking until soft and sweetened (~5 minutes). Stir green onions in using residual heat.