Cook quinoa to desired tenderness as directed on package (longer cooking times result in a softer texture). Cool completely.
Chop sun-dried tomatoes and thaw corn.
Chop onions and grate carrots; add to a large bowl along with sun-dried tomatoes, thawed corn, and remaining salad ingredients. Set aside.
Whisk together the olive oil and vinegar, then add to salad and toss to coat evenly.
Once quinoa has cooled, add to salad and toss once more (or leave the ingredients separate to be mixed when eaten). Serve at room temperature or chilled.