Heat oil in a large skillet and saute rice until golden. Stir in water, chicken broth and pepper. Increase heat to high and bring to a boil, and then reduce heat to low. Simmer, covered, for 20-25 minutes or unti rice is tender and liquid is absorbed. Stir in chickpeas. Preheat broiler. Transfer rice to an ovenproof serving dish. Top rice with tomato slices, and dot with butter. Broil for 2 or 3 minutes or until tomatoes are cooked. Garnish with chopped mint and serve.