Layer 2 paper towels on a baking sheet, lay out sliced tomatoes and zucchini and sprinkle with salt, flip over and sprinkle with salt again, and cover with another double layer of paper towels. (You may use flour sack or tea towels instead of paper.)
Let vegetables sit for 30 to 40 minutes to draw out liquid.
In the meantime, toss all 3 cheeses together. Measure out 1-1/4 cup of cheese for the mayo mixture and set aside the other half of cheese for filling.
With the 1-1/4 cup of cheese, add the mayonnaise and parsley (or extra dried basil), set aside,
Cook the bacon until crisp, remove from pan onto paper toweling .
Save about 1 tablespoon of bacon drippings in the same skillet, and cook onions & garlic in until tender and slightly browned. Drain on paper towel.
Corn Masa Crust
Mix dry ingredients to blend.
Using a large fork, cut in butter until crumbly, set aside.
In blender or food processor pulse corn and water together for about 15 to 20 seconds.
Stir the processed corn/water into crumbled flour/masa mixture. Stir together just until it makes a ball. With extra masa (or flour) roll dough out to fit a 10-inch pie plate, fold under and crimp edges.
Assembly & Baking
Preheat oven to 350 F.
In prepared crust, layer 1/2 cup of cheese on bottom of pie crust.
Layer half zucchini, layer half of basil, garlic/onions, half of bacon, and then half of tomatoes.
Make one more layer: 3/4 cup of cheese, layer of zucchini, remaining basil, garlic/onions and bacon, and final layer of tomatoes.
Spread the mayo/cheese mixture evenly over the top (I used my fingers). Bake at 350 degrees for 45 minutes (it should be bubbly and golden brown).
Let pie cool to room temperature before slicing & serving.