Drain the canned tuna well in a sieve. Press out the excess moisture firmly with the back of a spoon so the salad won't be too wet. Meanwhile, rinse the celery under running water, trim the ends, and cut the stalks into very fine dice.
Place the drained tuna in a bowl and break it apart with a fork into smaller pieces. Add the finely diced celery, the extra virgin olive oil, and the lemon juice. Season the mixture with salt and freshly ground black pepper.
Gently fold all the ingredients together. Do this with care so the tuna retains its structure and the salad doesn't become a smooth paste. Make sure the moist ingredients and seasonings are evenly distributed through the tuna.
Cover the bowl and place it in the refrigerator. Let the salad rest for fifteen to thirty minutes so the flavors can blend well. Remove the tuna salad from the refrigerator and serve immediately.