Sprinkle caviar in the bottom of a lightly oiled ring mold.
Peel and slice cucumbers.
Add 3/4 cups water and white wine vinegar each.
Cook slowly until tender.
Force the cucumber mixture through a fine sieve to make a smooth puree.
Add gelatin soaked in 3/4 cup cold water, a few drops of onion juice, 1 generous tablespoon of white wine, a few grains of cayenne and salt and pepper to taste.
Add a little vegetable coloring, strain and pour into the mold over the caviar.
Cool then chill until the gelatin is set.
Unmold the aspic on a serving dish.
Fill the center with chopped hard-cooked eggs mixed with chopped raw onion.
Garnish with mayonnaise forced through a pastry bag with a fancy tube