Spray the mug with avocado nonstick cooking spray, making sure to get the top as well.
In a bowl whisk together eggs, water, gruyere cheese, bacon, peppers, and asparagus. Season with salt and pepper. Pour into the greased mug. Place into the microwave and cook on high for 30 seconds. Then take out the mug stir and place it back into the microwave for an additional 30 to 40 seconds. Remove from the microwave. Using a knife cut around the exterior of the mug to help remove the omelet.
In a separate bowl, mix the mayo, chives, parsley, and lemon zest and season with salt and pepper.
Assemble the sandwich starting with the bottom of the bagel, slather the mayo on the base, then add the omelet, and tomato lettuce, and slather more mayo on the top of the bagel. Top the lettuce with the bagel top and serve! Enjoy!