Make barbecued pork loin: Preheat oven to 350 F.
Trim any fat from pork and pat pork dry. In a bowl stir together remaining barbecued pork loin ingredients. Add pork to barbecue sauce, turning it to coat.
In a small baking pan lined with foil roast pork 25 minutes, or until a meat thermometer inserted at least 2 inches into pork registers 155 F. Cool pork completely. Pork may be roasted 2 days ahead and chilled in a sealable plastic bag.
Cut pork into 1/4-inch-thick slices and cut slices into 1/2-inch squares. Cut leeks crosswise into thin slices and in a bowl soak in water to cover, separating slices into rings and agitating occasionally to dislodge any grit, 5 minutes. Lift leeks from water and drain in a colander. Trim snow peas and halve diagonally.
Make seasoning liquid: In a small bowl stir together seasoning liquid ingredients. Spread rice in a shallow baking pan and separate grains with a fork. In a deep 12-inch heavy non-stick skillet heat oil over moderately high heat until hot but not smoking and stir-fry leeks and ginger-root 1 1/2 minutes, or until leeks begin to soften. Add snow peas and toss to coat. Add rice wine or sake and stir-fry until snow peas are crisp-tender. Add rice and pork and cook, stirring frequently, 2 to 3 minutes, or until heated through. Stir seasoning liquid and add to fried rice, tossing to coat evenly.