Heat oven to 425F degrees while you dice the eggplants.
Sprinkle with olive oil and salt and spread the eggplant in a single layer on a parchment-covered baking sheet.
Bake for 20 minutes, turning them over halfway through, until the eggplant pieces begin to brown. Remove from oven and set aside.
Sautéed Onions
In a small sauté pan, heat 1 teaspoon olive or canola oil until hot.
Add the red onions and sauté until the onions are starting to caramelize (turn brown, but not black).
Remove pan from heat and set aside.
Quinoa & Corn
Toast a couple tablespoons of quinoa over medium-high heat in a dry medium pot until the quinoa is starting to brown and pop.
Add the water, rest of the quinoa, and corn and bring the water to a boil.
Reduce the heat to low, cover the pot, continuing to simmer the mixture until the quinoa is done, about 15 minutes. It will be fluffy with a light ring in the center; and all the water should be absorbed.
Dressing
Whisk the oil, lemon juice, garlic, pepper, and salt until well blended and emulsified.
Put It All Together
Combine the quinoa/corn mixture with the cooked onions, roasted diced eggplants and cherry tomato quarters.
Coat the combined mixture with the dressing and serve at room temperature or refrigerate for later. (It's also good hot.)