How to Make It
Light a grill or heat a cast-iron skillet. Drizzle the scallions with olive oil and season with salt and pepper. Grill over moderately high heat, turning once, until lightly charred, about 2 minutes. Let cool, then chop the scallions coarsely.
In a pot of salted boiling water, cook the pasta until al dente. Reserve 1 cup of the cooking water, then drain the pasta. Drizzle with olive oil and toss to coat.
Wipe out the pot and heat the 2 tablespoons of olive oil until shimmering. Season the scallops with salt and pepper. Add them to the pot and cook over high heat, stirring once or twice, until very lightly browned in spots and just firm, about 30 seconds. Using a slotted spoon, transfer them to a plate.
In the same pot, cook the charred scallions with the capers and olives over moderately high heat, stirring, until fragrant, about 30 seconds. Add the tomatoes and reserved water and cook, scraping up any browned bits from the bottom, until bubbling, about 5 minutes. Add the pasta and cook, stirring, until the sauce is slightly reduced and the pasta is coated, 3 to 5 minutes.
Fold the scallops and parsley into the pasta and season with salt and pepper. Transfer to shallow bowls or a platter. Drizzle with olive oil and serve.