Preheat the oven broiler. Place the pita breads on a baking sheet and warm under the broiler, 6 in. (15 cm) from the heat source, for a few seconds or until puffy, then carefully split them open through the middle and open out each one like a book. Return to the broiler and toast on each side or until lightly browned and crisp, about 2 to 3 minutes. Roughly tear the pita into bite-size pieces and set aside.
Whisk together the olive oil and lemon juice in a large serving bowl, and season lightly with salt and pepper. Add the scallions, tomatoes, cucumber and tuna, and toss gently to coat with the oil and lemon juice.
Add the parsley, cilantro, mint and torn pita pieces to the serving bowl and toss quickly to mix. Serve immediately.
Each serving provides calories 270, calories from fat 63, fat 7 g, saturated fat 1 g, cholesterol 13 mg, carbohydrate 38 g, fibre 4 g, sugars 6 g, protein 18 g. Choices per serving: Carbohydrate 2, Meat & Alternatives 2, Fat 1/2