In a bowl, combine the shrimp, bell pepper, mayonnaise, and harissa. Add the avocado and toss gently. Season with salt and pepper.
In a hot skillet, brown the inside and outside of the buns. Lightly spread the inside of the buns with mayonnaise. Garnish the bottoms with the shrimp salad and top with the lettuce. Close the buns and serve immediately.
Recipes with the "Healthy Pick" stamp have been evaluated by a registered dietitian member of the Ordre professionnel des diététistes du Québec.