Preheat oven to 400 F, and grease or oil pie dish.
Grate or use processor on zucchini.
Wrap grated zucchini in layered paper towels or cheese cloth. Squeeze and drain liquid from zucchini over sink. Place drained zucchini in large bowl.
Add all the remaining crust ingredients to the zucchini and mix together.
Place zucchini mixture into pie dish. Use the back of a spoon to spread mixture around pie dish, until dish is covered in zucchini crust mixture.
Bake zucchini crust in oven for 9 minutes.
Remove crust from oven (leave oven on). Set aside.
In large mixing bowl combine: eggs, egg whites, milk of choice, ground mustard, sea salt, and black pepper.
Grate or use processor on the cauliflower until rice texture forms.
Add cauliflower rice, chopped spinach, and chopped bacon to the egg mixture and combine.
Pour egg mixture into zucchini crust.
Place tomato slices on top of quiche.
Bake for 28 minutes, but check at 20 minutes to see if crust edges are browning too much.
Loosely cover the top of pie dish with a parchment paper sheet. Place back in oven for remaining 8 minutes, or until top is browned and center is firm and set.
Add optional cheese and put back in oven for 2 minutes.
Remove and let cool.
Slice and serve