For the apple and cucumber sandwiches, mix the apple with the lemon juice. Spoon the cream cheese into a bowl and stir in the herbs. Add the apple pieces and a little of the lemon juice.
To assemble sandwiches, generously swipe each slice of toasted sourdough with chimichurri cream cheese. Arrange roasted tomato slices over half the toasts. Top tomato slices with blanched asparagus.