Chop your veggies, and saute the red onion, red pepper, garlic and corn over medium heat until the onions are translucent.
Heat up the beans, and add a couple teaspoons of taco seasoning until the beans are as spicy as you like.
Meanwhile, add a couple teaspoons of taco seasoning to the veggies, and add in the spinach.
Start assembling your “lasagna”! In an 8×8 baking dish, start with a layer of the tomato sauce. You want just enough to cover the bottom of the baking dish, about ¼-⅓ cup. Then add ⅓ of the salsa, and a layer of the corn tortillas. You may have to cut some of the tortillas into quarters to fill the entire bottom of the baking dish (with no gaps).
Top the corn tortillas with ½ the refried beans, ½ of the veggie mixture, and a drizzle of the tomato sauce + salsa (about ⅓ the amount that's left of each).
More layering – top with the corn tortillas, the remaining ½ the refried beans, and the remaining ½ the veggie mixture, a drizzle of the tomato sauce + salsa (use the next ⅓ and you'll have ⅓ of the tomato sauce + salsa left for the final step).
Then top with the corn tortillas again, and the rest of the tomato sauce + salsa. Top that with the cheese, olives and tomatoes, and it’s ready to go into the oven! The tomatoes and olives will likely be at the very top of the casserole dish, that's ok!
Bake at 350 degrees for 15-20 min, until the cheese is bubbly and melted.