Start preparing the pesto by coarsely chopping the kale. Place the kale, walnuts, lemon, garlic, and parmesan in a blender or food processor, and purée until smooth. Add oil and process more. Season with salt and pepper and set aside.
Rinse the zucchini and cut thinly with a sharp knife. In a medium skillet, melt1 tbsp of butter over low to medium heat. Add slices of zucchini and stir to coat with melted butter. Season with salt and pepper.
While zucchini cooks, lightly dust fish filet(s) with lemon pepper. Once zucchini has cooked over medium heat for about 5-7 minutes (or until slightly tender), add remaining butter, and then place fish filets atop the zuchinni.
Grill for 2-3 minutes on each side, until cooked through. Serve fish over zucchini with several dollops of prepared pesto.