Heat charcoal or gas grill to 500°F and coat grates with oil. Grill pork tenderloins 90 seconds per side over direct heat, then move pork to indirect heat and continue cooking with grill lid closed for an additional 4-5 minutes per side, at 145°F. Remove from grill and rest on cutting board for 10 minutes.
While pork rests, lay bacon in single layer in cast-iron skillet and place over direct heat. Cook bacon until crispy, 5-7 minutes. Remove bacon from skillet and transfer to paper-towel-lined plate.
When bacon is cool enough to handle, roughly chop and combine in a medium bowl with parsley, almonds, garlic and lemon zest.
Cut tenderloin into ½-inch-thick slices and serve topped with bacon gremolata mix.