In a small bowl, mix together the soy sauce, vinegar, and honey. Set aside.
Heat a large skillet over medium-high heat, then add the chicken and black pepper and cook about 3 minutes, stirring occasionally.
Reduce heat to medium and add the garlic, ginger, and scallions, and cook for another minute.
Stir in the celery and the soy sauce mixture. Cook another 4-5 minutes, until the chicken is done. (Taste and add the optional salt, if you desire)
Remove from heat and sprinkle in the cashews.
Divide the chicken among 4 the lettuce leaves and serve.
Video
Notes
For a thicker sauce, dissolve a tablespoon of cornstarch in about 2 tablespoons of water, then slowly add to the skillet in step 4 and stir while heating until the sauce thickens.
Add extra scallions to the wraps after they're cooked and prepared for an even fresher taste.