Prepare the Asparagus - Cut off the tougher ends, about 1 to 2 inches. Rinse and dry the spears well. Place them on a sheet tray and drizzle with olive oil, then season with salt and pepper. Gently mix with hands to evenly distribute the seasonings.
Heat the Grill - Preheat the grill over medium-high heat, about 350 to 400ºF (177 to 204ºC). Carefully grease the cooking grates using tongs and a paper towel dipped in oil.
Grill the Asparagus - Add the asparagus and lemon halves to the grill, cover, and cook until light char marks appear, about 3 minutes. Flip and cook, uncovered, until tender, about 2 to 4 minutes depending on thickness.
To Serve - Transfer grilled asparagus and lemon to a serving plate.
Notes
Storing: Store in an airtight container in the fridge for 3 to 5 days.
Reheating: Microwave in 15 to 30-second increments until hot.