Drain the canned tuna and chickpeas thoroughly using a fine-mesh sieve to ensure the salad stays crisp and fresh.
Dice the cucumber into small cubes and halve the cherry tomatoes to create uniform, bite-sized pieces for the base.
Finely mince the red onion and fresh parsley to distribute their aromatic flavors evenly throughout the entire dish.
In a large mixing bowl, whisk together the extra virgin olive oil, fresh lemon juice, sea salt, and black pepper until fully emulsified.
Add the drained tuna, chickpeas, cucumber, tomatoes, and onion to the bowl, tossing gently to coat every ingredient in the dressing.
Sprinkle the crumbled feta cheese over the top and give it one final light toss before serving immediately for the best texture.