Preheat oven to 350 degrees F. Pull meat out of fridge to help come to room temperature. Pat dry and sprinkle with salt on both sides.
Place all ingredients for the cherry tomato salsa in a bowl and toss to combined. Place in fridge to marinate until meal is ready.
Steam the cauliflower until fork-tender, about 15 minutes. Transfer the steamed cauliflower to a high speed blender and puree until smooth. It should resemble smooth mashed potatoes. Add the garlic powder and salt and puree once more. Set aside.
For the chimichurri: place all the ingredients in a food processor or blender and puree until smooth. Set aside.
Heat up a grill pan or grill to a medium-high heat and grease to keep the meat from sticking. Place meat on grill and cook on both sides for about 5 minutes per side for medium-rare, depending on the thickness. Set meat on cutting board and cover with foil to let rest for about 10 minutes then thinly slice against the grain.
While the meat is resting, place tortillas on the baking sheet, spray with coconut oil and sprinkle a small pinch of salt on top of each. Place in oven to bake for 7-8 minutes, until brown and crispy.
Now all you have to do is build your tostadas: tortilla, 2 tablespoons of the cauliflower puree, 1-2 tablespoons chimichurri, sliced steak, cherry tomato salsa and garnish with cilantro and freshly crushed pink peppercorns!