In a small mixing bowl, whisk together dressing ingredients until well mixed and smooth. Set aside.
Cook pasta according to package directions just until al dented. Rinse, drain, and cool.
In a large skillet, cook the ground beef until no pink remains. Remove fat, stir in both taco sesonings, and cool.
In a large serving bowl, toss together pasta, beef, dressing, red onion, red pepper, tomatoes, and cilantro until evenly coated. Cover and refrigerate for 4-6 hours, or overnight, for best flavor
Just before serving, toss and adjust seasoning. Add more milk (I generally add about 1/4 -1/2 cup), as needed, to loosen dressing. Gently fold in cheeses, 3/4 of the bag of Doritos, and avocado. Pour onto decorative platter and garnished with more of the remaining crushed Doritos and 2 tablespoons of cilantro and serve. serve. Enjoy!