Heat 3 teaspoons of the oil in a large skillet over medium-high heat. Season the steak with 1/2 teaspoon salt and 1/2 teaspoon pepper. Cook to the desired doneness, 4 to 5 minutes per side for medium-rare. Transfer to a cutting board and let rest 10 minutes before slicing.
Meanwhile, return the pan to medium heat and heat 2 teaspoons of the oil. Season the zucchini with 1/4 teaspoon salt and 1/4 teaspoon pepper. Cook, cut-side down, covered, until browned and tender, about 6 minutes. Cut crosswise into 1/2-inch pieces and divide among individual plates.
In a small bowl, combine the lemon zest, garlic, herbs, bread crumbs, and the remaining oil. Sprinkle the bread crumb mixture over the zucchini and serve with the sliced steak.
Tip: You can cook both the zucchini and the steak outside on a grill using the same times as those in the recipe above.