Preheat oven at 180° C.
Mix salt, crushed peppercorns, one teaspoon mixed herbs and one teaspoon olive oil in a small bowl. Rub this mixture all over the chicken breasts and set aside to marinate for five to ten minutes.
To make pesto sauce, grind together garlic, walnuts and crushed peppercorns. Add Parmesan cheese, basil leaves and olive oil and grind to a smooth pastel. Transfer the pesto into a bowl, add salt and mix well.
Heat one tablespoon olive oil in a non-stick grill pan. Place the marinated chicken in it and grill, turning sides, till evenly done from both sides and grill marks appear on them.
Cut yellow and red capsicums into thin strips.
Spread the pesto sauce generously evenly on the pizza bases. Place red and yellow capsicum strips on them. Sprinkle salt, crushed peppercorns and remaining mixed herbs on top.
Cut chicken into thin strips and put over the capsicum strips.. Top with olives and cheese cubes.
Place the pizzas on a baking tray, keep the tray in the preheated oven and bake for ten to fifteen minutes or till the cheese melts.
Cut into wedges and serve hot.