Heat a large, dry pan over medium-high heat. Add walnuts and cook, stirring occasionally, until golden and fragrant, 3-5 minutes. Transfer to a plate. Heat a drizzle of olive oil in same pan over medium-high heat. Add asparagus, salt, and pepper. Cook, stirring, until browned and just tender, 4-6 minutes. Turn off heat; transfer to a plate. Wash out pan.