Place broccoli rabe in a large bowl. Toss with salt and one tablespoon olive oil. Let stand for 10 minutes. Preheat a grill to medium heat. Place broccoli in grill basket and put on grill. Grill until stems are crisp yet tender and leaves begin to char, about 3 1/2 minutes per side. In a small bowl, whisk together remaining one tablespoon olive oil and lemon juice. Remove broccoli from grill basket and place back in the large bowl. Toss with lemon vinaigrette and red pepper flakes. Serve immediately.
