Preheat the oven to 425°F (220°C). Place a cast iron or oven-safe skillet in the oven for 15-20 minutes to preheat.
Prep the zucchini. Add the zucchini to a plate and top liberally with salt. Let the zucchini sit for 15 minutes then pat dry with paper towels. Do not rinse.
While the zucchini sits, make the oil. In a small bowl, combine olive oil, pistachios, basil, lemon zest, lemon juice, grated garlic, salt, and red pepper flakes. Mix well to combine.
Remove the preheated skillet from the oven, drizzle about 1/2 tbsp-1 tbsp olive oil onto it, then add the zucchini slices face down. Place the skillet back in the oven for 30 minutes, flipping the zucchini slices halfway through cooking.
When the zucchini is done, allow it to cool for a few minutes. In a serving bowl, add arugula, cooked zucchini slices, most of the shaved Parmesan cheese, and a few spoonfuls of the prepared oil. Gently toss to coat.
Serve the salad topped with extra shaved Parmesan and oil, if desired. Enjoy!