Add the farro grains into a medium sauce pot, add 1&1/2 cups purified water, drizzle olive oil, salt, cumin and the rosemary spring, bring to boil over medium heat, then cover with a lid and simmer over low heat until the grains are cooked, about 20 minutes. Set aside.
Heat the grill.
In a medium bowl add the cherry tomatoes red pepper, onion, celery, mushrooms, carrots, drizzle with olive oil, season with salt, cumin and chili, and toss to coat evenly.
Grill the veggies, then transfer into a bowl.
In a small bowl mix the dressing ingredients.
To assemble the salad, pour evenly the dressing into the jars, add a layer of cooked farro, a tablespoon pesto, a few grilled veggies, diced fresh tomato and crumble feta cheese.
Lid the jar and shake before serving.