Begin by toasting the walnut halves in a skillet over medium heat, stirring them constantly until they become lightly browned, which should take about 5 minutes.
Remove them from the skillet and let them cool.
In a large bowl, toss together the toasted walnuts, mixed salad greens, orange pieces, thinly sliced red onion, and crumbled Gorgonzola cheese.
To prepare the citrus vinaigrette, add the freshly squeezed orange juice, sugar, olive oil, vegetable oil, balsamic vinegar, Dijon mustard, black pepper, and dried oregano to a lidded 1-pint jar.
Seal the jar and shake it vigorously to mix the dressing.
Drizzle the zesty citrus vinaigrette over the salad just before serving.
Enjoy your refreshing Orange-Gorgonzola Salad with the vibrant citrus vinaigrette!