Prepare the tuna: Drain the canned tuna thoroughly, pressing it gently with a fork against the side of the colander to remove any excess liquid. You want it flaky and dry, not wet. You'll notice the fish separates easily into tender, pale pink flakes.

Chop the vegetables: Dice the red onion, celery, and red bell pepper into small, even pieces. The onion should be fine enough that it blends into the salad without overwhelming each bite, releasing a sharp, fresh aroma as you cut.

Prepare the avocado: Halve the avocados, remove the stones, and scoop the flesh into a large salad bowl. Using a fork, roughly mash about half of the avocado until it's creamy and pale green, then cut the remaining avocado into 1cm cubes. This gives you a lovely mix of smooth and chunky textures.

Make the dressing: In a small jar, combine the lemon juice, extra virgin olive oil, and Dijon mustard. Screw the lid on tightly and shake vigorously until the dressing looks thick and slightly emulsified, with a pale, creamy colour. Give it a sniff — it should smell bright and tangy.

Combine everything: Add the flaked tuna, chopped vegetables, and snipped chives to the bowl with the avocado. Pour the dressing over the top. Using two large forks or salad servers, gently fold everything together. You want the dressing to coat every ingredient evenly without breaking the tuna flakes into a mush. The finished salad should look colourful, with specks of red pepper, green chives, and creamy avocado throughout.

Season and serve: Taste the salad — it should be bright and fresh. Season with salt and plenty of freshly ground black pepper. The pepper adds a gentle warmth that complements the tuna beautifully. Serve immediately on a bed of crisp lettuce leaves, which add a pleasant crunch and a fresh, earthy contrast to the creamy salad.