Preheat oven to 400. In a mixing bowl, add diced zucchini (about 1/2 pieces), and toss with olive oil, minced garlic, Italian seasoning, salt and pepper. Transfer to a roasting dish and place in oven. These should cook for about 30 minutes, tossing often, until tender.
In a food processor, add half of the lemon juice and olive oil, along with a handful of spinach. Puree until smooth. As a liquid forms, add additional spinach, minced garlic, olive oil, and lemon, to slowly incorporate until all is added. You can adjust lemon/olive oil to taste and liquidity preference. I like mine thicker, similar to a pesto.
Clean and place your salmon fillets on a baking dish. If using an air fryer, place about a tsp of the spinach puree on each and cook for about 12 minutes, until done. A conventional oven works just as well with the same process, but adjust cooking time accordingly, as this will take longer.
Plate roasted zucchini, topped with a salmon fillet, and add a generous amount of additional spinach puree for serving. If you'd like, sprinkle a little freshly grated parmesan cheese over the zucchini. Garnish with a wedge of lemon and enjoy!