Preheat oven to 375°F. Distribute vegetables on a parchment paper-lined baking sheet. Spray with olive oil and sprinkle salt, pepper and oregano on top.
Roast vegetables for 30 minutes, tossing halfway through, until edges are brown and vegetables are cooked through (soft to fork).
While the vegetables are roasting, cook quinoa according to package instructions. Set aside.
To make the dressing: Combine dressing ingredients in a small jar and shake to combine. Set aside.
To assemble the salad, add baby greens to a large bowl. Add the roasted vegetables and quinoa. Drizzle about half of the dressing on top. Toss to combine, taste, and add additional dressing, if desired. (Note: You can make all components of this salad ahead of time, but add dressing to salad prior to serving.) Enjoy!