Heat 1 tablespoon canola oil in a large flat-bottom wok or cast-iron skillet over medium-low heat until shimmering. Add scallions, shallot and ginger and cook, stirring occasionally, until starting to soften, 2 to 4 minutes. Increase heat to high and add the remaining 1 tablespoon canola oil and turkey. Cook, breaking up with a wooden spoon, until no longer pink and most of the liquid has evaporated, about 8 minutes. Add nuts and celery and cook, stirring occasionally, until the celery is soft, about 3 minutes more.

Whisk broth and cornstarch in a medium bowl until smooth. Whisk in lime juice, brown sugar, chile-garlic sauce, tamari and sesame oil. Add to the pan and cook, stirring frequently, until the sauce thickens, about 3 minutes.

Serve about 1/3 cup filling in each lettuce leaf. Garnish with scallions, sesame seeds and/or chiles and serve with lime wedges, if desired.