01 - Preheat oven to 425°F. Line a large baking sheet with parchment paper.
02 - In a bowl, toss halved baby potatoes with 1 tablespoon olive oil, 1/2 teaspoon paprika, 1/4 teaspoon salt, and 1/4 teaspoon pepper. Spread evenly on the prepared baking sheet.
03 - Roast potatoes for 15 minutes.
04 - While potatoes roast, combine chicken breasts with remaining 1 tablespoon olive oil, remaining paprika, garlic powder, oregano, remaining salt and pepper, and lemon juice. Let marinate for 10 minutes.
05 - Add red bell pepper and red onion to the partially roasted potatoes. Toss gently, then return to oven and roast an additional 15 minutes or until potatoes are golden.
06 - Heat a grill pan or skillet over medium-high heat. Grill chicken for 5-6 minutes per side, or until cooked through and juices run clear. Let chicken rest for 5 minutes, then slice.
07 - Arrange spinach leaves in serving bowls. Top with roasted potatoes, grilled chicken slices, roasted peppers and onion, and cherry tomatoes.
08 - Garnish with chopped parsley and serve with lemon wedges if desired.