Prepare the Quinoa:
Rinse the quinoa under cold water.
In a medium saucepan, combine the quinoa and water or chicken broth. Bring to a boil, then reduce the heat to low, cover, and simmer for about 15 minutes or until the quinoa is cooked and the liquid is absorbed.
Fluff the quinoa with a fork and set aside to cool slightly.
Grill the Chicken:
Preheat the grill or grill pan to medium-high heat.
Season the chicken breasts with salt, pepper, and 2 tablespoons of olive oil.
Grill the chicken for 6-7 minutes per side, or until the internal temperature reaches 165°F (75°C). Remove from the grill and let it rest for a few minutes before slicing.
Prepare the Mango and Red Onion:
While the chicken is grilling, peel and dice the mango, and finely chop the red onion.
In a mixing bowl, combine the mango, red onion, cilantro, lime juice, 1 tablespoon of olive oil, and honey (if using). Mix well and set aside.
Assemble the Dish:
In a large serving bowl, combine the cooked quinoa and the mango-red onion mixture. Mix until well combined.
Slice the grilled chicken breasts and place them on top of the quinoa salad.
Garnish with additional cilantro if desired.