Char the red bell pepper over a gas flame or under a broiler until the skin is blackened and blistered on all sides.
Place the charred pepper in a bowl and cover with a lid or plastic wrap for 5 minutes to steam, then peel away the skin, remove the seeds, and slice into thin strips.
Season the chicken breast evenly on both sides with the sea salt, black pepper, and garlic powder.
Heat the extra virgin olive oil in a stainless steel or cast iron skillet over medium-high heat.
Add the chicken to the skillet and sear for 6 to 8 minutes per side until the exterior is golden brown and the internal temperature reaches 165 degrees Fahrenheit.
Transfer the chicken to a cutting board and allow it to rest for 5 minutes before slicing into medallions.
In the same skillet, add the fresh baby spinach and sauté for 1 minute until just wilted.
To assemble, place the warm cooked quinoa in a bowl, layer with the wilted spinach and sliced chicken, and top with the roasted red pepper strips.
Finish the dish with a squeeze of fresh lemon juice over the top for brightness.