Wash and cut potatoes into chunks.
Boil potatoes until fork-tender.
Drain and steam-dry potatoes.
Preheat oven to 425°F.
Roast potatoes with olive oil, garlic powder, salt, and pepper.
Mix sour cream, cream cheese, dill, salmon, red onion, and lemon juice in a bowl.
Fold salmon mixture into roasted potatoes gently using a silicone spatula.
Top with extra dill, onion, and optional capers.
Serve immediately while warm.