Preheat the oven to 425°F. Add the quinoa, 1¼ cups water, and a pinch of salt to a small saucepan. Bring to a boil, cover, and reduce heat to low. Simmer until all of the water is absorbed and the grains begin to burst, about 15 to 20 minutes.
Add the butternut squash to a baking sheet with 1 tsp olive oil, 1 tsp of the sumac, and a pinch of salt and pepper. Roast squash until it begins to brown in places, about 15 to 20 minutes.
Peel and mince the shallot. Pick the parsley leaves. Thinly slice the cucumber. Thinly slice the radishes. Zest the lemon. Supreme the blood orange and lemon by trimming the ends and cutting away the peel and white pith. Working over a medium bowl, remove the flesh segments, then squeeze out the remaining juice.
Add the hazelnut to a small skillet over medium-high heat. Gently toast until aromatic and browned in spots, about 3 to 5 minutes. Remove skillet from heat and stir in the lemon zest.
Add the remaining 2 tsp sumac to the large bowl with lemon juice, and whisk in 1 tbsp olive oil. Add the blood orange segments, sliced cucumber, sliced radish, and parsley. Season with ½ tsp salt and ¼ tsp pepper. Toss the sumac herb salad until citrus and vegetables are evenly coated.
Divide the cooked quinoa between large bowls. Top with roasted butternut squash and the sumac herb salad. Sprinkle with chopped hazelnuts.