Preheat oven to 400 degrees.
Spread sweet potato bites on a rimmed baking sheet. Drizzle on olive oil, sprinkle with sea salt and pepper flakes. Toss to coat sweet potatoes and roast for 25 minutes, stirring once or twice to make sure sweet potatoes roast evenly and don’t stick to the pan.
Pour pumpkin seeds into an ovenproof shallow dish. Toast in the oven for 5 to 7 , or until golden brown and fragrant.
Meanwhile, make the dressing. Using a blender or food processor, blitz together ginger, orange juice and tahini for 1 minute or until smooth. Makes about 1/2 cup dressing, enough for the salad plus leftovers.
To assemble salad, toss together greens and quinoa or millet. Pour in 2 to 3 tablespoons of dressing, or until just moistened.
Scatter with chopped celery, chopped sweet potatoes and toasted pumpkin seeds. Drizzle another spoonful or two dressing on top or serve separately.