01 - Combine quinoa with 2 cups water in a medium saucepan. Bring to a boil, reduce heat to low, cover, and simmer for 15 minutes until water is absorbed. Remove from heat and fluff with a fork.
02 - Season chicken breasts with salt, pepper, and half the oregano. Heat 1 tbsp olive oil in a skillet over medium heat. Cook chicken 6-7 minutes per side until golden and cooked through (internal temperature 165°F). Let rest for 5 minutes, then slice thinly.
03 - While chicken rests, halve the cherry tomatoes, dice the cucumber and bell pepper, and thinly slice the red onion.
04 - Whisk together remaining olive oil, lemon juice, minced garlic, remaining oregano, salt, and pepper in a small bowl until emulsified.
05 - Divide spinach, quinoa, prepared vegetables, and sliced chicken among 4 bowls. Drizzle with dressing evenly. Top with crumbled feta and chopped parsley if desired.
06 - Serve immediately while chicken is warm, or store in airtight containers refrigerated for up to 3 days for meal prep.