For toasted tortillas, first dip them in cold water. Heat in a nonstick skillet over high heat. After about 30 seconds, flip. Remove from skillet and cover with a towl to steam for 5 minutes. The ideal tortilla should be soft, supple and moist with a hint of flakiness.
Microwave rice according to package directions. Transfer to a large bowl, and fluff with a fork. Set aside.
Process mayonnaise, buttermilk, cilantro, chipotle chile, lime juice, sugar, adobo sauce, cumin, and salt in a blender or food processor until smooth.
Gently stir chicken, beans, scallions, and 3/4 cup mayonnaise mixture into rice. Spoon about 1/2 cup chicken mixture into each tortilla. Top each with 1 tablespoon salsa and 1 tablespoon cheese. Serve with additional mayonnaise mixture.