Soak 16 wooden skewers in water for at least 30 minutes. Light a grill.
In a large skillet, cook the bacon over moderate heat, stirring, until crisp, about 15 minutes. Drain the bacon on paper towels. Transfer 1 tablespoon of the bacon fat to a medium bowl. Whisk in 2 tablespoons of the olive oil and the vinegar. Season with salt and pepper.
Cook the haricots verts in a saucepan of boiling salted water until crisp-tender, about 4 minutes; drain and rinse in cold water. Pat dry. Transfer to the vinaigrette and toss to coat.
In a bowl, toss the scallops with the remaining 2 tablespoons of oil. Thread 3 scallops onto 2 parallel skewers; repeat to make 8 brochettes. Season the brochettes with salt and pepper and grill over moderate heat until the scallops are medium rare, 2 to 3 minutes per side.
Mound the haricots verts on 8 plates. Top each salad with a brochette, sprinkle with the bacon and serve.
A creamy Chardonnay makes a like-with-like pairing with the rich bacon vinaigrette. The wine's acidity keeps the combination refreshing.