Preheat broiler or grill. Grill peppers until blistered (about 5 to 10 minutes), turning often.
Remove from oven or grill and place in paper bags for 5 minutes. Fold tops of the paper bags over and tape shut to enclose steam. Allow peppers to stand for 10 minutes or up to an hour. (This step can be done a day ahead of time).
After the 10 minutes have past, carefully release the steam from the paper bags. Peel the skin off the peppers, cut off their tops and slice into 1/2 inch strips. Place in a salad bowl and add the capers and parsley.
In a small bowl whisk together the olive oil and balsamic vinegar. Add the tomato to the bowl and drizzle over peppers. Stir gently to coat.
Taste, and season with salt and pepper as needed. Serve at room temperature.