In a medium sauté pan over moderate heat, warm the oil. Add the bell peppers, tomato, onion, ginger, garlic, crushed red pepper, cumin, cinnamon, turmeric, 1/2 teaspoon salt, and 1/8 teaspoon pepper and cook until slightly tender, about 10 minutes. Add 3 tablespoons water and chicken and continue to cook for several more minutes.
In a medium bowl, stir together the yogurt, cucumber, and the remaining 1 tablespoon water. Sprinkle with the remaining 1/2 teaspoon salt and 1/8 teaspoon pepper.
To serve: Place lettuce and a scoop of chicken masala mixture in the center of each tortilla or roll. Add a spoonful of the raita to each wrap, or serve it on the side, along with fresh mango slices.