In a tall cup using an immersion blender, combine mayonnaise, vinegar, lemon juice, mustard, capers, anchovies and garlic; blend until smooth. Stir in basil and chives.
On a large cutting board, cut baguette in half lengthwise. Spread both cut sides of baguette with half of the mayo mixture
Arrange toppings in the following order on bottom half: lettuce, tomato, artichokes, radishes, cucumber, tuna, eggs, onion and olives. Spoon remaining mayo mixture onto toppings. Garnish with basil and pepper. Cut baguette crosswise into four equal sections.
Summer in a sandwich! Amazing !