Preparation / Directions:
Cook chicken in medium-high skillet until juices run clear. Keep warm.
Slightly drain the beans and pour into a large mixing bowl. Add the next seven ingredients and mix well. From this mixture, remove 1 1/2 cups, draining off as much liquid as possible, and place into bowl and mash to a paste consistency. Mix paste back into the remainder of the beans.
To assemble, spread 1/4 of bean mixture onto each tostada, then sprinkle each with I cup of lettuce, followed by 2 sliced chicken tenderloins and 1/4 of the tomatoes. Top with avocados and cheese. Serve immediately.