Heat oil in a large saucepan over medium heat. Add onion and cook, stirring often, until softened. Add wild rice and barley; stir for a few seconds. Add broth and bring to a simmer. Reduce heat to low, cover and simmer until the wild rice and barley are tender and most of the liquid has been absorbed, 45 to 50 minutes.
Meanwhile, toast pine nuts in a small, dry skillet over medium-low heat, stirring constantly, until light golden and fragrant, 2 to 3 minutes. Transfer to a small bowl to cool.
Add pomegranate seeds, lemon zest, parsley and the toasted pine nuts to the pilaf; fluff with a fork. Serve hot.
To Make Ahead: Prepare through Step 2. Cover and refrigerate for up to 2 days. To reheat, place in a baking dish, add 1/4 cup water and cover. Microwave on High for 10 to 15 minutes or bake at 350 degrees F for 25 to 30 minutes. Tip: To seed a pomegranate and avoid the enduring stains of pomegranate juice, work under water. Fill a large bowl with water. Hold the pomegranate in the water and slice off the crown. Lightly score the fruit into quarters, from crown to stem end. Keeping the fruit under water, break it apart, gently separating the plump seeds from the outer skin and white pith. The seeds will drop to the bottom of the bowl and the pith will float to the surface. Discard the pith. Pour the seeds into a colander. Rinse and pat dry. The seeds can be frozen in an airtight container or sealable bag for up to 3 months.