In a large bowl, soak the barley in water for 1 hour and then drain. Meanwhile, light a grill. Brush the zucchini, eggplant, and peppers with 1⁄4 cup of the olive oil and season with salt and pepper. Grill the vegetables, turning occasionally, until tender and charred, 10 minutes. Transfer to a board and cut into 1⁄2-inch pieces.

Bring a medium pot of salted water to a boil and add the barley. Turn the heat down to medium and cook until the grains are tender, about 45 minutes. Drain the barley and set aside to cool to room temperature.

In a large bowl, whisk the remaining olive oil with the lemon juice, cumin, coriander, and garlic, and then stir in the reserved barley; season with salt and pepper, and transfer to a platter. Arrange the grilled vegetables, the feta, arugula, cilantro, parsley, pistachios, scallions, and chile over the barley, and serve at room temperature.