Heat a large skillet over medium heat. Coat both sides of the mini corn tortillas with cooking spray. Place the tortillas in the hot skillet, pressing them flat, and cook for 3-4 minutes on each side, or until golden brown and crisp.
Place the chicken, cilantro, green onion, and jalapeno on the chopping board. Using a chef's knife, chop the ingredients and toss them together. Season with a bit of sea salt, freshly cracked pepper, garlic powder, cumin, and coriander, to taste.
Toss together and place into a glass bowl. Heat in the microwave for 20-30 seconds, or until warmed through.
Slather the bottom of the crisp mini tostada shells with a bit of sour cream followed by some mixed greens, chicken mixture, avocado, tomato, and cotija cheese. Serve with salsa on the side. Enjoy.