For sauce, in a small bowl stir together water, dry sherry or wine, soy sauce, cornstarch, and sugar. Set aside.
Pour the cooking oil into a wok or large skillet. (Add more oil as necessary during cooking.) Preheat the wok or large skillet over medium-high heat. Stir-fry the ginger in hot oil for 15 seconds. Add the fresh asparagus (if using) and squash; stir-fry for 3 minutes. Add the thawed asparagus (if using) and green onions; stir-fry about 1- 1/2 minutes more or until the asparagus is crisp-tender. Remove vegetables from wok.
Add tofu to the hot wok or skillet. Carefully stir-fry for 2 to 3 minutes or until lightly browned. Remove from wok. Stir the sauce. Add sauce to hot wok. Cook and stir until thickened and bubbly. Return cooked vegetables and tofu to the wok. Stir all ingredients together to coat with sauce. Cover and cook about 1 minute more or until heated through. Stir in pine nuts or almonds. Serve over rice. Makes 4 servings.