1. Heat wok or large skillet over medium-high heat; add 1 teaspoon oil and mushrooms; cook, stirring, about 3 minutes. Transfer to plate; cover.
2. Add 1 tablespoon oil to wok, and cook pork 2 minutes, turning often. Stir in 2 tablespoons hoisin and 1 teaspoon ginger. Cook, turning, 2 minutes or until cooked through. Transfer to plate; cover.
3. Add remaining 1 teaspoon oil to wok. Cook bok choy with remaining 1 teaspoon ginger, stirring often, 2 minutes or until almost tender. Add 1/4 cup water, grapefruit juice, and remaining 1 tablespoon hoisin; cook 2 minutes or until tender. Turn off heat.
4. Divide rice into 4 bowls, and top with pork, mushrooms, bok choy, and grapefruit. Sprinkle with peanuts and chives.