In a medium bowl, combine cucumber, scallions, carrot shreds, rice vinegar, cilantro, and red pepper flakes. Mix well adn refrigerate until your ready to assemble your cups.

Bring a pan misted with nonstick spray to medium-high heat on the stove. Add chicken and sprinkle with garlic powder. Cook chicken, stirring occasionally, until cooked through, about 4 minutes.

Place chicken and peanut dressing or sauce in a bowl and toss to coat. Remove veggie mixture from fridge.

To assemble, evenly distribute the veggie mixture and the chicken among the lettuce cups.