Bring a large saucepan of water to a boil for the pasta. Bring a small saucepan of salted water to a boil for the peas. Cook the peas until tender, about 3 minutes. Drain the peas, reserving ¼ cup of the cooking water. Transfer the peas and the reserved cooking water to a food processor along with the lemon juice, 2 tablespoons of the oil, 1 teaspoon salt, and the pepper. Process until thoroughly blended. Return the pea pesto to the small saucepan and keep warm.
Prepare the grill for direct cooking over high heat (450° to 550°F).
Blot the scallops dry, and remove and discard the tough side muscle that might be left on each one. Brush the scallops on both sides with the remaining 1 tablespoon oil.
Cook the pasta until al dente, according to package directions.
Brush the cooking grates clean. Grill the scallops over direct high heat, with the lid closed, until they are cooked through and just opaque in the center, 4 to 6 minutes, turning once. Remove from the grill. Drain the pasta, reserving ¼ cup of the cooking water. Toss the pasta, the reserved cooking water, and the pea pesto together. Top the pasta with the scallops, and garnish with the chives and bacon.