Place a steamer insert into a saucepan; fill with water to just below the bottom of the steamer. Cover pan and bring the water to the boil. Add beetroot, cover pan and steam until just tender, 7 to 10 minutes. Set aside.
Add quinoa and 475ml water to a saucepan; cook over high heat until starts to boil. Reduce the heat to medium-low, cover and simmer until the quinoa is tender and the liquid has been absorbed, about 15 minutes.
While the quinoa is cooking, whisk olive oil, red wine vinegar, sugar, garlic, salt and black pepper together in a large bowl.
Remove quinoa from heat, then immediately add half of the vinegar dressing while fluffing the quinoa with a fork; reserve remaining dressing. Cover and refrigerate quinoa until cool, at least 1 hour.
Stir spring onions, rocket, goat cheese, beetroot and remaining dressing into cooled quinoa mixture. Toss lightly before serving.