Bring a large pot of salted water to a rolling boil. Add the French green beans, asparagus, and sugar snap peas, cooking for 1 minute until vibrant and crisp. Immediately drain and plunge the vegetables into an ice bath to stop the cooking process, preserving their bright color and crunch. Let them sit for a few minutes, then drain again and set aside.

In a skillet over medium heat, melt the butter and 1 tablespoon of olive oil. Add the walnuts and sauté for 2-3 minutes until they become fragrant and lightly toasted. Stir in the panko bread crumbs, cooking until golden brown, about 3-4 minutes. Finally, mix in the lemon zest and crushed red pepper, then remove from heat and set aside to cool.

In a large mixing bowl, whisk together the lemon juice, lemon zest, and minced garlic. Slowly drizzle in the remaining olive oil while whisking vigorously to create a smooth dressing. Season the mixture with kosher salt and freshly ground black pepper to taste, ensuring it's flavorful and well-balanced for your Lemony French Green Bean Asparagus Salad.

Add the cooled blanched vegetables to the bowl with the dressing. Toss gently to coat the green beans, asparagus, and sugar snap peas in the flavorful mixture, making sure they are evenly coated. Taste and adjust seasoning, adding more salt or pepper if needed, to highlight the vibrant flavors of the salad.

Transfer the dressed vegetables to a serving platter. Top generously with the walnut-panko mixture, allowing it to add a delightful crunch. Sprinkle shaved Parmesan, fresh mint leaves, and sliced scallions over the salad for added garnish and aroma. Serve immediately for the best texture or keep toppings on the side if storing leftovers.