Add zucchini to a large saute pan, sprinkle with a little salt and cook until they are softened and slightly browned. Season the ground beef with the onion powder, cumin, garlic powder, chili powder, salt, and add the diced onion. Cook until the beef is cooked and the onions are softened. Add the grilled zucchini on bottom, followed by the ground beef and onion mixture. Add the cheese, salsa, cilantro, sour cream and guacamole. Enjoy!