Preheat the oven to 425 degrees F (220 degrees C).

Spread sweet potato and red onion on a baking sheet; drizzle with 1 tablespoon olive oil. Season with salt and black pepper; toss to coat.

Bake in the preheated oven until sweet potatoes are tender, 20 to 25 minutes.

Meanwhile, bring chicken broth and quinoa to a boil in a saucepan. Reduce heat to medium-low, cover, and simmer until quinoa is tender and broth is absorbed, 15 to 20 minutes.

Heat 1 tablespoon olive oil in a skillet over medium heat. Add 2 cloves garlic and ginger; cook and stir until fragrant, about 1 minute. Add chicken; cook until no longer pink in centers and juices run clear, about 6 minutes per side. An instant-read thermometer inserted into centers should read at least 165 degrees F (74 degrees C). Cut chicken into 1-inch pieces.

Whisk lime juice, peanut butter, soy sauce, honey, and remaining 1 garlic clove together in a bowl; whisk in remaining 1 tablespoon olive oil and sesame oil until dressing is smooth.

Divide quinoa among bowls; top with chicken, sweet potato mixture, spinach, and avocado. Sprinkle cilantro and sesame seeds over top; drizzle with dressing.