Mix together the dressing ingredients and set aside (Saco brand buttermilk powder is very good and usually easy to find in the supermarket baking aisle.)
Heat the olive oil in a skillet over medium heat and cook the black beans, the corn kernels, ¼ teaspoon chili powder, ¼ teaspoon garlic powder and ¼ teaspoon cumin for about 5 minutes
Remove the bean and corn mixture from the skillet and set it aside. Add the shrimp to the same skillet (might need a spritz of nonstick spray) and turn the heat up to medium-high. Cook the shrimp until they turn pink and translucent.
Arrange the lettuce, the bean/corn mixture, the tomatoes, avocado, chopped green onions, shredded cheddar, tortilla sauce, dressing and cooked shrimp in a salad bowl.
