In a small bowl combine water and cornstarch. Set aside.

Heat a large skillet over medium-high heat. Add oil, swirling to coat the pan. Add the shrimp, and cook for 2 minutes, or until starting to turn pink. Mix in snow peas, garlic, black pepper, and salt. Cook for 1 minute. Remove from heat.

In a small saucepan combine chicken stock, brown sugar, and fish sauce. Heat over high, and bring to a boil. Stir in the cornstarch mixture. Cook for 30 seconds, or until it starts to thicken, stirring constantly. Pour over shrimp.

Return shrimp the heat, and cook for 2 minutes or until hot.

Serve over brown rice.