To make the dressing, add all the ingredients, except the water, to a blender and blitz on high until smooth and creamy, adding 1 tablespoon of the water at a time, as needed, to allow the sauce to blend.
Put the lettuce, cucumber, cherry tomatoes, and chicken in a large bowl, then pour half the dressing (reserving the remaining for another time) over the top and toss to coat the salad.
Divide the salad between four bowls and top with the toasted “croutons” to serve.
Fill a medium saucepan with water and place over high heat. Once boiling, add the eggs and cook, undisturbed, for 8 minutes. Remove the eggs with a slotted spoon and run them under cool water until cool to the touch. Peel and finely chop.
Add the egg, cucumber, celery, mustard, dill, and the dressing to a large bowl and toss to combine. Divide the toast among four serving plates, top with the egg salad and a slice of ham and serve.
