Cut tofu into 1-inch cubes; drain for 5 minutes on paper towels.
Combine water and next 6 ingredients in a small bowl; stir until cornstarch is dissolved. Set aside.
Heat a nonstick skillet over medium-high heat. Add peanuts; cook 3 to 4 minutes or until lightly browned, stirring often. Set aside.
Heat oil in a large nonstick skillet over medium-high heat; arrange tofu in a single layer. Cook 5 minutes on each side or until lightly browned. Remove from skillet.
Coat pan with cooking spray. Add carrot, bell pepper, and bok choy; sauté 6 minutes or until white part of bok choy is crisp-tender. Increase heat to high; add tofu, peanuts, snow peas, and soy mixture. Bring to a boil; reduce heat, and simmer 1 1/2 minutes or until slightly thick, stirring constantly. Serve over noodles.