Combine the diced green pepper, tomato, cucumber and red onion with the parsley and dried mint and set aside.
Whisk together the harissa paste, extra-virgin olive oil, lemon juice, salt, and pepper, then pour over the diced vegetables. Stir well to combine.
Tip onto a large serving platter and arrange the tuna, quartered eggs and olives over the top.
Notes
Vegetables: Remove the watery seeds from the tomatoes and cucumber for a cleaner dice and crisper salad.
Harissa: Brands vary in heat, so begin with a little and add more to your taste.
Garnishes: Tuna, boiled eggs and olives are traditional additions but can be included or omitted as you like.
Variations: Try adding diced radish, green chilli, capers or green apple.
Make ahead: Chop the vegetables and boil the eggs a few hours in advance. Keep them refrigerated and add the dressing and garnishes shortly before serving.
Storage: Refrigerate leftovers in an airtight container for 1–2 days. The vegetables will soften over time. The salad is not suitable for freezing.
Tuna - I prefer tuna in water because it has a lighter flavour and contains less oil.