We found traditional peaches work better in this dish than white peaches, which have more sugar and water and don't hold up as well on the grill.
Preheat oven to 350°. Arrange 1/4 cup pecans, chopped, in a single layer in a shallow pan. Bake 8 to 10 minutes or until toasted and fragrant, stirring after 5 minutes.
Peel and chop 1 peach. Cut each of remaining 3 peaches into 8 wedges.
Process chopped peach, green onions, next 7 ingredients, and, if desired, tequila in a food processor 10 to 15 seconds or until smooth. Add oil, and pulse 3 to 4 times or until thoroughly combined.
Coat cold cooking grate of grill with cooking spray, and place on grill. Preheat grill to 350° to 400° (medium-high). Brush both sides of peach wedges with 1/3 cup peach dressing.
Grill peach wedges, covered with grill lid, over 350° to 400° (medium-high) heat 2 to 3 minutes on each side or until grill marks appear.
Divide Bibb lettuce and bacon slices among 4 plates or shallow bowls. Top with grilled peach wedges. Sprinkle with feta cheese and pecans. Serve with dressing.
Note: You can also use a grill pan to get those beautiful grill marks on the peaches.