Add the potatoes to a large pot of salted boiling water and simmer until tender. Drain and dry completely with paper towels.
Heat olive oil in a large skillet over medium heat.
Add the onion and bell pepper and saute in hot oil until vegetables are soft, about 6-8 minutes.
Add the garlic and cook for 1 more minute.
Add the cooked sweet potatoes, kale, vinegar, and chili flakes (if using) and stir to combine.
Season with salt and pepper.
Cover and cook for 5 minutes, stirring occasionally.
Add the quinoa and stir to combine.
Gently press hash down with a spatula and make four egg-sized wells in the hash with the back of a spoon. Crack eggs into the wells.