Preheat oven to 400. In the bowl of a food processor, pulse parmesan until finely grated. Add garlic and pulse until mixture is homogenous. Add kale and parsley, and pulse until mixture is finely chopped but not paste-like. Scrape down sides of bowl. Add zest, lemon juice, and walnuts. Pulse until walnut is very finely chopped. From the opening on top, stream in olive oil with blade running. Scrape down sides of bowl as needed. Season with salt and pepper.