Place asparagus spears in a large baking dish and drizzle with olive oil. Season lightly with kosher salt and to taste with pepper. With your hands, gently toss to coat evenly.
Divide asparagus spears into 6 bunches of 4 to 5 spears. Wrap each bundle with 1/2 slice of bacon, pressing or tucking under ends to secure or securing with soaked toothpicks (optional), taking care to minimize areas where bacon overlaps. (see recipe photos and video)
Cook bacon wrapped asparagus bundles on hot grill over direct heat with lid closed (recipe note #3). Grill for 5 to 8 minutes per side, until asparagus is tender and lightly charred and bacon is cooked through with crispy edges. Gently turn bundles half way through cooking time to cook evenly. Transfer to platter and serve.
If you plan to secure the bacon strips with toothpicks, be sure to soak them in water for 15 minutes. You don't want them to catch on fire!
To trim asparagus spears, snap off the woody bottom of each spear where it breaks naturally. For tidy spears, slice off the jagged bottoms (optional).
Having the grill lid closed helps these bundles cook evenly, but keep an eye out and check on them if there seems to be excess smoke. Better to add a couple of minutes to the cooking time then end up with burned asparagus bundles.