Spicy Chicken Salad Cups

Name: Spicy Chicken Salad Cups
Ingredients: 1/2 cup mayonnaise; 2 teaspoons sambal oelek or chile-garlic sauce; 1 teaspoon Dijon mustard; 1/2 teaspoon sesame oil; 1 (2-pound) rotisserie chicken, skin and bones discarded, meat pulled into bite-size pieces; 1/3 cup water chestnuts, coarsely chopped; 2 scallions, white and green parts thinly sliced; Kosher salt; Freshly ground black pepper; 12 Bibb or iceberg lettuce leaves; 1 Hass avocado, peeled and cut into 12 slices; Lime wedges, for serving