In a small bowl, whisk together the olive oil, chili powder, cayenne pepper, sea salt, and black pepper to create a spicy marinade.
Place the chicken breast in a shallow dish, coat thoroughly with the marinade, and let it sit for at least 20 minutes to absorb the flavors.
Combine the dry quinoa and water in a small saucepan, bring to a boil, then reduce heat to low, cover, and simmer for 15 minutes until the water is absorbed.
Preheat your grill to medium-high heat and lightly oil the grates.
Grill the marinated chicken for 6-7 minutes per side or until the internal temperature reaches 165 degrees Fahrenheit.
While the chicken cooks, grill the sliced red bell peppers and red onions until they are tender and show charred grill marks.
Slice the grilled chicken into thin strips and fluff the cooked quinoa with a fork.
Assemble the bowl by layering the baby spinach and quinoa, then topping with the grilled chicken, charred vegetables, and fresh avocado slices.
Garnish with fresh cilantro and a squeeze of lime juice before serving.