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 fully absorbed. Remove from heat and fluff with a fork.
02 - Season chicken breasts generously with salt, pepper, and half the oregano. Heat 1 tbsp olive oil in a skillet over medium heat. Cook chicken for 6-7 minutes per side until golden brown and internal temperature reaches 165°F. Transfer to a plate and rest for 5 minutes before slicing thinly.
03 - While chicken rests, halve the cherry tomatoes, dice the cucumber and bell pepper into uniform pieces, and thinly slice the red onion.
04 - In a small bowl, combine remaining olive oil, lemon juice, minced garlic, remaining oregano, and season with salt and pepper. Whisk vigorously until emulsified.
05 - Divide baby spinach evenly among 4 bowls as a base. Top with cooked quinoa, arranged vegetables, and sliced chicken. Drizzle dressing evenly over each bowl. Sprinkle with crumbled feta and fresh parsley if desired.
06 - Serve immediately while chicken is still warm. For meal prep, store components in separate airtight containers or fully assembled bowls in the refrigerator for up to 3 days.