Add a new preparation to your tortilla rotation: toasting the tortilla until it's perfectly crispy. (Tostada, as you may have guessed, means “toasted” in Spanish.) Then pile on the flavorful fixings: chayote, seasoned turkey, pickled red onion, avocado, sour cream, and cheese. (And don’t forget the lime zest to give it that breezy citrus hint.) There's no dainty way of eating the resulting deliciousness, but you won't care: Toasty, crumbly tostadas will become your tortilla go-to.
Peel and halve onion. Slice thinly. Zest limes and halve. Juice three halves and quarter remaining half. Place onion in a mixing bowl with lime juice and a pinch of salt. Toss to coat and marinate until tender, at least 15 minutes. Trim chayote ends and halve lengthwise. Use a spoon to scoop seed out of each half. Cut halves into ½" dice. Mince cilantro (no need to stem).
Toast the Tortillas
Place tortillas on prepared baking sheet and lightly coat both sides with cooking spray. Toast until crisp and golden brown, 7-10 minutes. Remove from oven and set aside. While tortillas toast, cook chayote.
Cook the Chayote
Place a medium non-stick pan over medium heat. Add 2 tsp. olive oil and chayote to hot pan. Stir occasionally until lightly browned and tender, 5-8 minutes. Season with half the cilantro, 1 tsp. lime zest (reserve remaining of both for garnish), and a pinch of salt and pepper. Remove to a plate. Reserve pan; no need to wipe clean.
Cook the Turkey
Return pan used to cook chayote to medium-high heat. Add 1 tsp. olive oil and ground turkey to hot pan. Stir occasionally until browned, 4-7 minutes. Stir in seasoning blend and ¼ cup water. Cook until water has evaporated, 2-4 minutes. Remove from burner.
Prepare the Avocado
Halve avocado and remove pit by carefully tapping pit with the blade of your knife so it sticks. Gently twist knife to release pit. Scoop out flesh with a spoon. Cut into ¼" slices lengthwise.
Finish the Dish
Place avocado on tortilla and add turkey. Add chayote and pickled red onion (to taste). Sprinkle on cheese, remaining cilantro, and add a dollop of sour cream. Top with remaining lime zest (to taste). Repeat with remaining tortillas. Serve with lime quarters on the side.