Preheat the oven to 375 degrees F.

In a large bowl, toss chicken with all of the seasonings. Cover with plastic wrap, and allow chicken to marinate for at least 30 minutes.

Preheat a grill or a large grill pan over medium-high heat. Grill chicken on each side for 1 to 2 minutes per side. If your pan is not oven-safe, then transfer chicken to a baking dish and let finish cooking in the oven for 7 to 9 minutes, or until fully cooked through. Let the chicken cool, slice it into julienne strips, and reserve.

Heat a pan of canola oil until the temperature of the oil reaches 375 degrees F. Fry the tortilla strips until crisp, about 2 minutes. With a spider or slotted spoon, remove the strips from the pan and let drain on a paper towel.

In a large mixing bowl, toss the lettuce, onions, and tomatoes with 1 cup of the Tomatillo Vinaigrette. Toss until all ingredients are well mixed. Divide the lettuce mixture evenly among 4 dinner plates or individual salad bowls. Arrange 4 tomato quarters around the edge of each salad.

In a circular pattern, arrange the chicken atop each salad, alternated with the avocado and poblano slices in between. Sprinkle about 1/4 cup cheese over each salad. Drizzle the remaining vinaigrette over the chicken and vegetables. Garnish with the tortilla strips and cilantro.

Add the tomatillos to a pot of simmering water, and blanch for 5 minutes. Drain the tomatillos into a colander, and allow them to cool slightly.

In blender, combine all of the ingredients except the oil. Puree the mixture for 15 seconds, and then continue blending for 30 seconds, slowly drizzling in the olive oil through the top until the dressing emulsifies.