01 - Preheat oven to 425°F. Line a baking sheet with parchment paper.
02 - Arrange green beans and red onion slices on the prepared baking sheet. Drizzle with 1 tbsp olive oil, season with salt and pepper, and toss to coat evenly. Roast for 18 to 20 minutes, stirring halfway through, until tender and lightly caramelized.
03 - While the vegetables roast, combine quinoa and water or broth in a medium saucepan. Bring to a boil, then reduce heat to low, cover, and simmer for 15 minutes until the liquid is fully absorbed. Remove from heat, fluff with a fork, and let rest covered for 5 minutes.
04 - In a small bowl, whisk together the remaining olive oil, lemon zest, lemon juice, honey or maple syrup, Dijon mustard, salt, and pepper until well combined.
05 - In a large bowl, combine the cooked quinoa, roasted green beans and onions, and cherry tomatoes. Drizzle with half the dressing and toss gently to coat evenly.
06 - Transfer to a serving platter or individual bowls. Top with crumbled feta, toasted nuts, and chopped parsley. Drizzle with the remaining dressing and serve warm.