Wash the little potatoes thoroughly under cold water to remove any dirt. Place them in a large pot, cover with water, add a generous pinch of salt, bring to a boil over medium-high heat, then reduce to a simmer and cook for 15-20 minutes until fork-tender.
Preheat your oven to 425°F (220°C) to achieve crispy smashed potatoes.
Drain the cooked potatoes and let them cool for a few minutes. Place them spaced out on a baking sheet lined with parchment paper, then gently smash each potato with a fork or potato masher until flattened but not broken apart.
In a small bowl, mix olive oil, garlic powder, smoked paprika, salt, and pepper to taste. Drizzle this mixture generously over the smashed potatoes. Squeeze the juice of half a lemon over the top.
Roast the potatoes in the preheated oven for 20-25 minutes, flipping halfway through, until golden brown and crispy.
While roasting, combine Greek yogurt, minced garlic, chopped parsley, chives, and a pinch of salt in a mixing bowl. Mix well to make the creamy yogurt sauce.
Remove the roasted potatoes from the oven, let cool slightly, then serve warm topped or sided with the garlic yogurt sauce. Garnish with additional parsley and chives if desired.