Heat the vegetable oil in a large skillet or wok over high heat.
Add the minced garlic and sauté for about 30 seconds until fragrant.
Add the shrimp to the skillet, stirring frequently, and cook until pink, about 2-3 minutes.
Toss in the bell pepper and snap peas; stir-fry for another 2-3 minutes until tender-crisp.
In a small bowl, combine soy sauce, oyster sauce, cornstarch, and a splash of water.
Pour the sauce over the stir-fry mixture, tossing gently to coat evenly.
Finish with a drizzle of sesame oil and season with salt and pepper to taste.