In a small saucepan, combine the quinoa and water. Season with salt, and bring to a boil. Reduce the heat to a simmer; cover and cook until the water has absorbed (you should see little divots in the quinoa), about 13 to 15 minutes. Remove the pot from the heat and let sit, covered, 5 minutes to steam. Take off the lid, and fluff the quinoa with a fork. Transfer it to a large bowl and let cool.
In the meantime, make the dressing. In a small bowl combine the orange juice, rice vinegar, garlic and gochugaru. Let sit 5 minutes to allow the flavors to meld. Whisk in the oil.
To the bowl with the quinoa, add the edamame, cucumber, pickled ginger and scallions, and season with salt and pepper. Add the dressing and toss to coat (at this point the salad can be refrigerated for up to 2 hours). Right before serving, fold in the avocado, and season with a touch more salt, pepper or gochugaru, if needed.