Bring the salted water to a boil in a saucepan. Add the rinsed quinoa, reduce to low heat, and simmer for 15–20 minutes until all the water is absorbed. Spread on a plate to cool.
Spread the sunflower seeds, pumpkin seeds, sesame seeds, and hazelnuts on a small baking sheet. Toast in a 320°F oven for about 15 minutes until fragrant. Let cool.
Slice the cucumber and pepper into thin strips. Halve the cherry tomatoes. Slice the green onion. Chop the parsley.
Press the cut side of each apricot half into the sugar. Sear sugar-side down in a medium-hot skillet for 2–3 minutes until caramelized. Do not let the sugar burn.
Whisk together the olive oil, balsamic vinegar, and honey.
Toss the arugula, cooled quinoa, and chopped vegetables in a large bowl. Spread onto a serving platter, scatter the toasted seeds, arrange the grilled apricots on top, and drizzle with the dressing.