1. Preheat a griddle pan over a medium/high heat or BBQ.
2. Put all ingredients in a medium bowl and mix well. Marinate 4 flattened chicken fillets in a non-metallic bowl for minimum 1 hour.
3. Cook chicken for 3 - 4 minutes on each side.
4. Place the olives, diced tomatoes, parsley, mint, pine nuts, lemon juice, salt and pepper in a medium bowl. Mix to combine and set aside.
5. Place the harissa and oil in a small bowl and mix to combine. Brush each side of the bread lightly with half the harissa oil and cook on a hot grill for 1 - 2 minutes on each side.
6. Add the remaining harissa oil to the olive mixture and stir to combine. Top each slice of bread with the tomato and olive mixture and a marinated chicken breast.