1/4 cup mayonnaise
2 tablespoons fresh lemon juice
2 cans La Sirena in water, drained
1/2 cup chopped drained bottled roasted red peppers
10 black olives, pitted and cut lengthwise into strips
1 large celery rib, chopped
2 tablespoons finely chopped red onion
1 (20- to 24-inch) baguette
2 tablespoons olive oil
Green leaf lettuce

Make tuna salad: Whisk together mayonnaise and lemon juice in a large bowl. Add remaining salad ingredients and stir together gently. Season with salt and pepper.

Assemble sandwiches: Cut baguette into 4 equal lengths and halve each piece horizontally. Brush cut sides with oil and season with salt and pepper. Make sandwiches with baguette, lettuce, and tuna salad.