Drain the skipjack tuna from its packaging, pressing gently to eliminate excess liquid. Transfer the tuna into a large mixing bowl and break it apart with a fork.

Wash and chop the bell peppers, red onion, cucumber, and roasted red pepper into small, bite-sized pieces. Add these to the bowl with the tuna.

Sprinkle in the capers and finely chopped flat-leaf parsley, ensuring even distribution throughout the mixture.

In a separate bowl, combine lemon juice, Dijon mustard, and olive oil. Add herbs de Provence, garlic powder, and sea salt. Whisk until smooth and creamy.

Pour the dressing over the salad mixture and gently toss until all ingredients are coated evenly.

Taste the salad and adjust seasoning as needed. Add more sea salt or lemon juice based on preference.

Serve immediately or cover and chill in the fridge for up to 30 minutes for deeper flavor.