Bring a small pan of water to a rolling boil and gently lower the eggs into the water. Cook for 8 minutes to hard boil the eggs. Remove from the water and sit in a bowl under running water until completely cold.
Meanwhile, place the mayonnaise in a bowl with the paprika, if using, and a pinch each of salt and pepper.
Once cold, tap the eggs all over to break the shells. Peel away the shell and roughly chop the hardboiled eggs. Mash into the mayonnaise with the chopped chicken and either spread on bread to make sandwiches or spoon onto baked potatoes. Scatter with the cress to serve.