How to Make It
Light a gas grill. Brush the scallions with vegetable oil and season lightly with kosher salt. Grill them over moderate heat, turning, until they are softened and lightly charred, about 3 minutes total. Let cool and cut into 3/4-inch lengths. Leave the grill on.
Fill the peach pit cavities with the scallion pieces and season with salt. Wrap two strips of bacon around each peach half and secure the bacon strips with toothpicks.
Lightly brush the stuffed peaches with vegetable oil and grill them cut side down over moderately high heat until they are lightly charred, 1 to 2 minutes. Carefully flip the peaches and grill them over moderately low heat, turning occasionally, until they just start to soften and the bacon is crisp at the edges, 7 minutes. Transfer to a platter and serve.