Mix together the harissa, 5 tablespoons of olive oil and the lime juice in a small bowl, using a small wire whisk. Stir in the chopped coriander, mint and a grinding of pepper. Adjust seasoning to your taste, adding a little more lime or harissa if wished.
Heat the remaining teaspoon of oil in a heavy-based pan, add the almonds and fry until golden, shaking the pan occasionally so they are evenly coloured. Tip onto kitchen paper to drain, season and set aside.
Cut the Romaine into chunky slices, stopping about a third from the top (separate that top third into leaves. Put the lettuce into a large bowl and scatter over the almonds, spring onions, olives and remaining coriander leaves. Give the dressing a quick whisk then drizzle over the salad.
The salad can be made up to an hour ahead and chilled. Keep the dressing separately at room temperature, then drizzle it over just before serving.
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