Mix chimichurri ingredients in a bowl and let stand at room temperature for at least 15 minutes.
Preheat the oven to 400 degrees F.
Add the potatoes and 1/8 cup salt to a large saucepan. Bring to a boil and then reduce to a simmer. Cook the potatoes until fork-tender, about 20 minutes. Drain the potatoes.
Add 1/4 cup oil to a baking sheet and spread it around. Gently transfer potatoes to the baking sheet. Shake the pan back and forth so the potatoes roll in the oil.Smash the potatoes with the back of a fork. Don't crush them, just smash them until they break open. Drizzle with more oil and season with salt and pepper.
Bake the potatoes for 30 minutes or until they're starting to turn golden brown on the top. Transfer the potatoes to a serving platter and drizzle on the chimichurri sauce.