In a small jar or bowl, combine the olive oil, apple cider vinegar, Dijon mustard, maple syrup, and garlic powder.
Secure the lid and shake vigorously, or whisk until the dressing is smooth and emulsified.
Divide the baby arugula and romaine between four serving bowls.
Evenly top each bowl with the cooked millet, sliced peaches, diced tomatoes, cucumber, corn, avocado, and pumpkin seeds.
Drizzle generously with the prepared dressing.
Toss gently before serving to coat all ingredients evenly. This Summer Harvest Millet Bowl is best enjoyed immediately while the vegetables are crisp and fresh.