In a large bowl, combine the shredded chicken, chopped romaine lettuce, Caesar dressing, grated Parmesan cheese, garlic powder, black pepper, and salt. Mix well until all ingredients are evenly coated.
Heat a skillet over medium heat and add the olive oil.
While the skillet is heating, assemble the sandwiches by placing a generous portion of the chicken Caesar mixture on two slices of whole grain bread. If using, add halved cherry tomatoes on top of the mixture.
Top each sandwich with the remaining slices of bread.
Place the sandwiches in the heated skillet and cook for about 3-4 minutes on each side, or until the bread is golden brown and crispy.
Remove from the skillet, slice in half, and serve immediately.