Heat oil in a large nonstick skillet over medium-high heat. Once oil is hot, add chopped zucchini and sauté until lightly browned, about 5-7 minutes. Add butter to skillet, and let it melt. Add green onions and garlic, and continue to cook until garlic is fragrant, about 30 seconds. Stir in 2 teaspoons of the Cajun seasonings.