In a large bowl, combine 3 ounces cream cheese, 3 tablespoons mayonnaise, salt and pepper until smooth. Stir in the tuna, celery and green pepper.
In another bowl, combine the carrots, onion and remaining cream cheese and mayonnaise. Spread 1/3 cup tuna mixture on four slices of white bread; top with a slice of whole wheat bread. Spread 1/4 cup carrot mixture on the whole wheat bread; top with a slice of white bread.