Preheat oven to 450°F degrees and coat two large baking sheets with cooking spray. Toss potatoes with 1/2 tsp oil and season to taste with salt and pepper and optional spices or herbs. Spread potatoes evenly across one baking sheet, leaving space between cubes. Place baking sheet in oven and roast for 30 minutes or until well browned, stirring half-way through. Meanwhile, toss tomatoes with remaining 1/2 tsp oil and season to taste with salt and pepper and optional spices or herbs, and spread tomatoes evenly across second baking sheet. Roast for 15-20 minutes or until softened. Season to taste with fresh herbs, salt and pepper. Next, place chicken on toasted muffin and top with lettuce, tomato and mayonnaise. Serve with roasted potatoes and tomatoes.