Slice the zucchini into thin strips (they shouldn't fall apart, just thin enough to be considered lasagna noodles). Sprinkle both sides of the zucchini slices lightly with salt to draw out the moisture, then set aside. I keep my slices on a couple of cutting boards.
Heat the olive oil in a large skillet with high sides, over medium heat, then add the onions and green peppers. Saute the veggies for about 5 minutes, or until the peppers begin to soften and the onions are translucent.
Add the ground beef, salt, and black pepper to the skillet. Cook the mixture until the beef is completely browned. Drain off any excess fat. Add the garlic, stirring to combine the garlic with the other ingredients in the skillet.
Combine the tomato paste and water in a small bowl, and then pour it into the beef mixture, along with the diced tomatoes, wine, oregano, and thyme. Simmer for about 5 minutes, stirring frequently, until much of the moisture is gone.
Pat the zucchini dry with a paper towel (or kitchen towel), then lay several zucchini "noodles" in a single layer in the bottom of a 9x12 baking dish (you can also use a 9x9 pan).
Preheat the oven to 375F.
Spread 1 1/4 cup layer of meat sauce evenly in the base of the baking dish, then evenly distribute a 1/4 cup of ricotta cheese over the meat (think: small blobs scattered over the sauce). Finally, sprinkle some of the mozzarella cheese over the sauce and ricotta.
Repeat the layers (zucchini, meat sauce, ricotta, mozzarella) 3 times to build the lasagna.
Top with the final layer of zucchini, then sprinkle evenly with parmesan cheese and the remaining mozzarella cheese.
Cover the lasagna with foil and and bake for 30 minutes. Remove the foil and bake 20 more minutes. The lasagna will bubble and the cheese should be golden brown.
Let the lasagna sit for 10-15 minutes before serving.
Notes
I recommend cutting the zucchini in half, and then cutting the zucchini halves into strips/noodles. I've found this to be the easiest method for cutting even zucchini strips/noodles. Of course, this may vary with the length of your zucchini. I love the addition of red wine. It adds a subtle flavor to the sauce. If you'd prefer to skip this ingredient, you're welcome to do so. The sauce and lasagna taste great even without the wine.