Pour 2 tablespoons of vegetable oil into a large skillet and heat over medium-high heat.
Generously season the chicken and shrimp with salt and pepper.
Sprinkle cornstarch over the chicken and shrimp, ensuring they are fully coated.
Add the coated chicken to the skillet and cook until it turns slightly golden, about 2 minutes per side.
Remove the chicken from the skillet and set it aside.
In the same skillet, add the shrimp and cook until they turn slightly pink, about 2 minutes per side.
Remove the shrimp from the skillet and set them aside.
In a small saucepan, combine 2 tablespoons of water, 1 tablespoon of soy sauce, 1 teaspoon of lime juice, 1/4 cup of peanut butter, 1 tablespoon of sugar, 1 teaspoon of rice vinegar, and 1/8 teaspoon of red pepper flakes.
Heat the mixture over medium heat until it gently bubbles, stirring constantly to ensure a smooth blend.
Cover the saucepan and remove it from the heat, letting the flavors meld together.