1) To make the spread, place the cream cheese, goat cheese, garlic, thyme, parsley, 5 tbsp milk, salt and pepper in the bowl of an electric mixer fitted with the paddle attachment. Beat on medium speed until well mixed. Add an additional tbsp of milk if the spread is very thick.
2) To make the sandwiches, spread each slice of bread with the goat cheese spread. Slice the cucumber into thin rounds and arrange on top of the bread slices. Cut the sandwiches into halves, thirds or triangles.