Soak the shrimp in milk for 20-30 minutes. The milk will eliminate any fishy odor or taste. After soaking, rinse well and drain.
Heat a thin layer of vegetable oil in a frying pan. Fry the tortilla on each side until crispy and stiff. Drain on a paper towel-lined baking sheet. Repeat with the remaining tortillas.
Preheat the broiler.
Sprinkle the shrimp with chili powder and salt. Toss until well coated.
Place the shrimp on a baking sheet and broil for 3 minutes. Check to make sure the shrimp are pink before removing them from the oven. Keep an eye on them, so they do not burn. If you are using large-sized shrimp, it may take longer than 3 minutes. I used small, salad-sized shrimp, so these take a minimum amount of time.
In a bowl, combine the lime juice, sour cream, garlic powder and remaining chili powder. Stir and set aside.
To build the tostada, place the crispy tortillas on a large baking sheet. You may need to use more than one baking sheet to fit them all.
Top with the shrimp and cheese.
Heat under the broiler until the cheese is melted.
Top the tostada with the cabbage mix, avocado, cherry tomatoes, hot sauce, cilantro and Chili Lime Cream Sauce.
Serve with some lime wedges and some extra avocado and salsa.