Nicoise Tuna Sandwich

Ingredients

• of white onion

  thinly sliced
  ¼ unit
• of a small red onion

  thinly sliced
  ⅛ unit
• extra-virgin olive oil

  plus additional for drizzling
  2 tablespoons
• red wine vinegar

  plus additional to taste
  1 tablespoon
• salt

  plus additional to taste
  ¼ teaspoon
• black pepper to taste
  1 unit
• x 6-ounce can tuna packed in olive oil (see above) including olive oil
  1 unit
• lemon juice to taste
  1 unit
• kaiser rolls

  plain
  2 unit
• lettuce leaves

  combination of Boston, green-leaf, or other green leafy lettuce
  1 unit
• tomato slices
  8 unit
• – 8 hard-boiled eggs slices
  6 unit
• anchovy fillets

  drained
  4 unit
• niçoise olives
  1 unit
• scallions

  chopped
  1 unit
• radishes

  sliced
  1 unit