Heat olive oil in a large skillet over medium-high heat for 1 minute. Add onion to pan; cook until soft (4-5 minutes). Add garlic to pan; cook 2 minutes. Add chicken, 1/2 teaspoon salt, and 1/4 teaspoon pepper to pan; sauté until cooked through (3-4 minutes). Transfer to a plate to cool. Combine mayonnaise, lemon juice, 1 tablespoon chopped fresh dill, turmeric, 1/2 teaspoon salt, and 1/2 teaspoonpepper in a large bowl; whisk well. Add cannellini beans, artichoke hearts, and chicken mixture to bowl, stirring to combine. Chill 1 hour. Place chicken salad evenly into butterhead lettuce leaves; garnish with 1 1/2 teaspoons chopped fresh dill.