Drain the cans of tuna into a fine sieve with a bowl underneath, gently flake the tuna and set aside
Thinly slice the tomato, red onion, black olives, cucumber and wash & pat dry the leaves of lettuce
To make the garlic mayo aioli, add the mayonnaise into a bowl, finely grate in the garlic, add in the lemon juice, extra virgin olive oil and season with sea salt & black pepper, whisk together until well mixed
Cut the baguette into two 6 inch (15 cm) pieces and then cut each one open
Add the lettuce in the bottom piece of the baguette, then the slices of tomato, season with sea salt & black pepper, then add in the tuna, black olives, red onion and cucumber, add a dollop of the garlic mayo aioli over the top piece of baguette, then place over the sandwich, enjoy!