In a 2-1/2 qt saucepan, bring farro, 1/2 teaspoon salt and water to a boil. Reduce heat and cook according to package directions (20 min).
Shred cooked beet into a large shred, place in a bowl and cover with apple cider vinegar and a pinch of salt. Cover and reserve.
Trim kale, rinse and dry in a salad spinner. Chop roughly into 1" strip.
Chop shallots. Slice mushrooms.
Place a large skillet over medium high heat. Add the walnuts and toast them for a couple minutes until they are fragrant. Remove the walnuts and set them aside.
Add 2 tbsp olive oil to skillet. Add shallots, mushrooms and a pinch of salt. Saute for 5 minutes, stirring frequently, until mushrooms have rendered all liquid.
Add kale to the pan and a pinch of salt. Toss and cook until kale is wilted but still bright green. Add a tbsp of balsamic vinegar, toss and set aside.
When farro is cooked, drain it.
Drain the vinegar from the beets.
Place 1/4 of the kale mix on each plate. Top with 1/4 of the farro. Drizzle 1 tsp balsamic vinegar and 1 tsp olive oil on each plate.
Top with 1/4 of the beets, 1/4 of the feta cheese and 1/4 of the walnuts. Grind some fresh pepper on top to taste.