1. In a very large bowl, combine the ginger, garlic, parsley, vinegar and olive oil and season with salt and pepper. Set aside 1/2 cup of the marinade. Season the vegetables with salt and pepper and toss well to combine. Let the vegetables marinate about 1 hour.
2. Preheat the grill. When it is too hot to hold your hand six inches above the grill for more than 5 seconds, it's ready. Grill the vegetables until charred and tender, about 8 minutes for zucchini, squash and scallions, 10 minutes for peppers and 15 minutes for the red onions.
3. Transfer the vegetables to a large serving platter and drizzle with the reserved marinade. Serve at warm or room temperature.