Stir together sauce ingredients. Set aside while preparing stir fry.
Pat tofu dry with a towel to remove excess water. Cut into 1/2-inch cubes.
Heat a large skillet or wok over medium-high heat. Add oil and tofu; stir frequently until tofu is lightly browned, about 5 minutes. Add snow peas, carrots and onion. Stir-fry about 5 minutes until vegetables are cooked, but still crisp. Stir in prepared sauce and cook 1-2 minutes until sauce is slightly thickened. Serve immediately.