Preheat the oven to 400 degrees F. Season the peppers with olive oil, salt and pepper. Place on a baking sheet and roast until the skin blisters, about 15 to 20 minutes. Remove from the oven and cool completely. Remove the skin and seeds. Slice the peppers into strips, about 1/2-inch thick. Place the potatoes into a saucepan, over medium heat and cover with water. Season with salt. Bring to a boil, reduce the heat to medium low and simmer until tender, about 12 minutes. Remove from the heat and drain. Toss the potatoes with olive oil, salt and pepper. Season the tomatoes with olive oil, salt and pepper, and set aside. Season the onions with olive oil, salt and pepper, and set aside. On a large platter, arrange the potatoes, peppers, tomatoes, and onions over half of the platter. Preheat the grill. Season the sardines with salt. Let stand for 1 hour and then rinse off and pat dry. **Salting the fish before cooking results in a firmer flesh. Season the sardines with olive oil, salt and pepper. Place on the grill and cook for 3 to 4 minutes on each side, depending on size. Grill the sardines in batches, keeping the cooked sardines warm. Place the sardines on the platter. Drizzle the sardines with olive oil. Garnish with parsley. Serve with a glass of the Vino Verde.