Preheat the oven to 400F/ 204C. (If making the Pickled Red Onions, start with those.)
Spread the sweet potatoes on a baking sheet and drizzle 1 tablespoon olive oil over them then add a pinch of salt and pepper and toss to coat. Then spread evenly on the pan and roast for about 20-25minutes, stirring halfway through, until sweet potatoes are fork tender.
While the sweet potatoes are cooking, chop your kale, add it to a large bowl and massage with the 1/2 tablespoon of olive oil for about a minute. Set aside.
For the Maple Tahini Dressing- In a small bowl add the dressing ingredients except for the olive oil and whisk until smooth. Then drizzle in the olive oil while whisking continuously. Season as necessary with a little more salt, pepper or lemon juice if desired.
Add the dressing and the quinoa to the chopped kale and toss to combine. Then once the sweet potatoes are done and slightly cooled, add them along with the rest of the salad ingredients, minus the feta, and give another gentle toss. Top with the feta & Enjoy!
In a small pot, add all of the ingredients for the onions except the red pepper flakes. Bring to a boil over a medium flame then turn off the heat and let sit until cooled, about 30 minutes to an hour. Once cool, add the red pepper flakes if desired and transfer to a jar with a lid to store in the refrigerator. (They can be kept in refrigerator for 2-3 weeks.) ** If you like crunchier pickled onions, add the sliced onions to the hot liquid after you turn the heat off.
*If making this ahead of time, keep all the ingredients separate and toss just before serving.