Cook rye berries in a large saucepan of boiling salted water until tender, about 60 minutes. Drain and set aside.
While grains cook, preheat oven to 425°F. Toss carrots in 1 Tablespoon of the oil, coriander, 1/2 tsp. of the cumin, and 1/2 tsp. of the salt. Place in a single layer on a foil-lined baking sheet. Roast, tossing occasionally, until carrots are tender, about 40 minutes.
Place remaining 2 Tablespoons oil, 1/4 tsp. cumin, 1/2 tsp. salt, lemon juice, shallots, honey, and black pepper in a large bowl; whisk to combine. Let stand 15 minutes. Stir in chopped cilantro, cooked grains, and carrots.
Divide evenly onto each of four plates. Sprinkle pistachios and pomegranate arils evenly over top. Garnish with extra cilantro, if desired.