In a wok, drizzle peanut oil and heat to medium heat. Add garlic and ginger. Fry until fragrant, 30 seconds. Stir in the chicken, breaking it up into small pieces, and the cayenne pepper. If the chicken gets too dry, add up to 1/2 cup water. Fry, stirring often, until cooked through. Remove from heat and add the rice powder, red onion, red pepper, cilantro, and mint.

In a small bowl, whisk together the fish sauce, lime juice, and sugar. Toss with the chicken. Serve at room temperature with the lettuce leaves and rice.