In a medium saucepan over medium heat, combine the rinsed farro, 2 cups of water and a pinch of salt. Bring the farro to a boil, cover the pot and lower the heat to a simmer. Cook the farro for 20 minutes, or until it’s cooked through and still has a bit of chew. Drain the farro and set aside.
Rinse out the saucepan that you used for the farro and fill it with about 2 inches of water. Place the pot over medium heat. Let it come to a light boil. Set up an ice bath in a medium sized bowl.
Trim the tough stems off of the broccoli rabe and cut it into bite-pieces. Drop half of the cut broccoli rabe into the saucepan and place the lid on it right away. Allow the rabe to steam for about 3-4 minutes, or until tender and lightly wilted. Transfer the steamed broccoli rabe to the ice bath. Repeat this blanching process with the remaining broccoli rabe.
Remove the stems from the kale and chop the leaves into bite-sized pieces. Place the chopped kale into a large bowl. Trim the fennel bulb, reserving some of the fronds, and remove the core. Shave the fennel with a mandolin right over the bowl with the kale. Remove the apple core and shave it with a mandolin over the large bowl. Remove the tough outer peel of the red onion and shave it with a mandolin over the large bowl.
Squeeze all of the excess water out of the blanched broccoli rabe and place it in the large bowl with the kale and other shaved fruits/vegetables. Add the cooked farro to the bowl as well.