You should know about the sauce on top of these. I know I can be dramatic. But listen. There's peanut butter in this. Coconut milk. Spicy Sambal. Lots of basil and cilantro. Lots of lime juice. Structurally, these are super simple. Chicken, tostada shell, the sauce and a few garnishes. You could even add more veggies like thinly sliced red bells and/or fresh bean sprouts. Or more sauce. You can even leave the shells on the soft side if you're feeling like tacos. Whatever you do, add more sauce
For the tostadas: Heat the oil in a medium nonstick skillet over medium-high heat. Sprinkle the chicken with some salt and pepper and sear, covered, on one side for 5 minutes. Flip the chicken, cover and sear for 4 minutes more. Transfer the chicken to a plate to rest for 5 minutes, then thinly slice.
Meanwhile, place the tortillas on a parchment paper-lined baking sheet, lightly coat each with the cooking spray and bake for about 10 minutes. For an extra crisp, run them over an open flame on your stove top.
For the sauce: Combine the cilantro, coconut milk, peanut butter, lime juice, Sambal Oelek and basil in a food processor and blend until you get a smooth sauce.
Evenly divide the chicken over the tostada shells. Top with the cabbage and a drizzle of the sauce. Sprinkle with the peanuts and cilantro leaves and serve with the lime wedges.