Rinse and pat dry the chicken breast, trim off any excess fat, and rub with 1 tablespoon of the Blackening Spice. Heat the oil in a cast iron skillet over high heat, add the chicken and cook until brown and cooked through, about 6 minutes on each side. Remove to a cutting board, cool slightly and slice. Cover to keep warm.
Heat the beans in a small pot over low heat until heated through and keep warm. Prepare the remaining ingredients and have them ready for assembly.
Heat a griddle or cast iron pan to high and toast the tortillas on both sides until crisp (if you try to fold them, they will crack).
Lay out 1 tortilla on a cookie sheet and evenly spread it with half of the beans, 1/3 of the cheeses, 1/2 of the blackened chicken, 1 tablespoon of the green onions, and cover with a second tortilla. Repeat this layering order with the remaining ingredients. Finish with the third tortilla and garnish with the remaining cheese, cilantro and diced tomatoes. Bake for 5 minutes. Remove from the oven and portion with a slicing knife into 4 wedges. Serve with the Black Bean Salsa and Chipotle Ranch Dressing.
Blackening Spice Rub:
Combine all of the ingredients in a small bowl. Store in an airtight container.
Black Bean Salsa:
Gently mix all of the ingredients in a large container. Cover and refrigerate for 20 minutes.
Chipotle Ranch Dressing:
Process all of the ingredients in a blender until smooth. Pour the dressing into a serving bowl, cover and refrigerate for 30 minutes before serving.