Place the mayo, lime juice, chipotles, adobo sauce, sweetener, cumin and salt in your blender or food processor and puree until smooth. Use 1 chipotle chili for tame spice (note that it mellows when used on the salad) and 2 for high heat.
If needed, thin the dressing with the milk beverage, 1 teaspoon at a time, to reach your desired consistency.
For the 7 Layer Salad
Divide the lettuce between four bowls. Layer the beans, tomatoes or red peppers, corn, olives, and avocado on (I prefer that order), topping with the chips.
Drizzle the chipotle dressing on the salads or serve it on the side. You may or may not have some leftover, depending on how heavy you pour it on. Cover and refrigerate any leftovers for up to 3 days.