Nicoise Tuna Sandwich

Ingredients

 * ¼ of white onion, thinly sliced
 * ⅛ of a small red onion, thinly sliced
 * 2 tablespoons extra-virgin olive oil, plus additional for drizzling
 * 1 tablespoon red wine vinegar, plus additional to taste
 * ¼ teaspoon salt, plus additional to taste
 * black pepper to taste
 * 1 x 6-ounce can tuna packed in olive oil (see above) including olive oil
 * lemon juice to taste
 * 2 kaiser rolls, plain
 * lettuce leaves, combination of Boston, green-leaf, or other green leafy lettuce
 * 8 tomato slices
 * 6 – 8 hard-boiled eggs slices
 * 4 anchovy fillets, drained
 * niçoise olives
 * scallions, chopped
 * radishes, sliced

Directions

 * 1) Combine the red and white onion with 2 tablespoons extra-virgin olive oil,1 tablespoon red-wine vinegar, ¼ teaspoon salt, and several grinds of black pepper in a bowl.
 * 2) Using your hands, mix and squeeze everything together for 5 minutes. (Don't rush through this part; the onions need time to release their juices and mellow.)
 * 3) Work in can of tuna in olive oil, including the oil.
 * 4) Season with fresh lemon juice, red-wine vinegar, and salt, then add pepper to taste.
 * 5) Cut kaiser rolls in half crosswise and spread each bottom half with lettuce leaves.
 * 6) Use a couple of varieties—whatever looks good—for the difference in texture.
 * 7) On top of each lettuce layer, arrange 4 tomato slices (skip this step if you don't have good — really good — tomatoes on hand).
 * 8) Then add about half the tuna mixture and 3 to 4 slices of hard-boiled egg.
 * 9) Crisscross each sandwich with 2 drained anchovy fillets and strew with niçoise olives (pit them if desired), chopped scallion greens, and sliced radishes.
 * 10) Then drizzle generously with more olive oil and top with the remaining kaiser halves, pressing gently but firmly.