Crisp baguette in hot oven, then cool to handle. Cut baguette in half lengthwise, on an angle, then split each half lengthwise.
Put about 1 inch of water, the bay leaf, peppercorns, and juice of 1/2 the lemon into a small skillet and bring to a simmer over medium heat. Add the tuna steak, cover, and simmer until cooked through, about 4 minutes. Remove tuna from the water and allow to cool. Place tuna in a bowl and separate with a fork. Add capers, red onion, artichokes.
For olives, if they're pitted, coarsely chop them. If the olives have pits, place an olive or 2 on your cutting board. Turn your knife sideways and place the flat of the blade on top of the olives -- just like peeling garlic -- whack the heal of your hand on knife and the pits of the olives will be exposed. Remove pits and chop.
Add olives and parsley to tuna mixture. Squeeze the juice of half a lemon into the bowl. Squeeze lemon halves holding cut side upright, allowing juice to spill over sides. The seeds will stay with the lemon half, rather than falling into your salad. Add black pepper to the bowl and drizzle salad liberally with evoo, extra virgin olive oil. Toss tuna salad and adjust pepper and evoo to your taste. Pack the tuna salad on to baguette halves and set tops in place. Press down to set the bread and salad together. The bread will absorb the evoo and salad juices -- YUMMY! Cut each half baguette in half again, making 4 sandwiches, total.
To get the juices flowing, place whole lemon in microwave on high for 10 seconds.