While the potatoes and eggs are boiling, finely slice the green spring onions or scallions, finely dice the purple shallots and gherkins, and grate the carrot and cheese.
When the potatoes and eggs are boiled, cool in cold water, pat dry, peel, and finely dice. With the boiled eggs, you’ll need to separate the egg white from the yolk and dice separately.
Divide the ingredients into four, then, using teaspoons and beginning with the tuna, carefully add each ingredient to each of four glasses, taking care not to smudge the interiors of the glasses, and patting each layer down evenly.
To each glass add the tuna, then green onions/scallions, egg whites, a tablespoon of mayonnaise, cheese, purple shallots, grated carrot, gherkins, egg yolks, and fresh dill.
Serve with bowls and spoons, and condiments such as mayonnaise, vinegar, salt, pepper, perhaps paprika or chilli flakes, maybe a small dish of capers, and more fresh dill. Suggest that your guests upend their glass of salad into the bowls, combine, and add additional condiments if they like.