Step 1: Preheat the grill to high.
Step 2: Toss the green beans with the 1-1/2 tablespoons of sesame oil and place them in a grill basket. Grill, occasionally tossing with tongs, until the beans are charred in places and tender-crisp, 8 to 12 minutes depending on their thickness. Grill the scallions at the same time; they will take about 5 minutes. Let the grill cool to smoking temperatures (225 to 250). Make sure it is set up for indirect grilling.
Step 3: In the meantime, combine the garbanzo beans, kidney beans, and edamame in a large disposable foil pan. Place the pan with the mixed beans in the center of the grill grate away from direct heat. Add a handful of wood smoking chips to each pile of coals, or enclose all the chips in an aluminum foil smoking pouch. (If your gas grill has a box for wood chips, use that.) Smoke the beans for 1 hour, stirring occasionally. The beans can be smoked at a previous grill session, if desired, and refrigerated for up to 2 days.
Step 4: When the green beans are cool, slice them on a diagonal into 1-inch lengths. Trim off the root ends, then do the same with the scallions. Transfer to a large mixing bowl.
Step 5: Gently stir in the cooled smoked beans. (A large rubber spatula works well.)
Step 6: Make the dressing: In a small mixing bowl, whisk the vinegar and sesame and vegetable oils to combine. Whisk in the sugar or honey until dissolved, then add salt and pepper to taste. (The dressing should be tart and highly seasoned, but well-balanced.) Stir in the cilantro, if using.
Step 7: Pour the dressing over the bean mixture and stir gently to combine. Chill for 1 to 2 hours before serving to let the flavors develop. Re-stir before serving.
Our thanks to the sponsors of Project Smoke Season 3:
Steven Raichlen’s Project Smoke is a production of Maryland Public Television, Barbacoa, Inc., and Resolution Pictures. © 2017 Barbacoa, Inc.