In a large bowl, combine olive oil, honey, soy sauce, minced garlic, grated ginger, cayenne pepper, salt, and pepper. Add the chicken cubes and mix until well coated. Let it marinate for at least 30 minutes (or up to overnight in the fridge for deeper flavor).
While the chicken marinates, prepare the skewers. Alternate threading the marinated chicken, diced mango, red bell pepper pieces, and red onion wedges onto the skewers, creating a colorful pattern.
Preheat a grill or grill pan over medium-high heat. Once hot, place the skewers on the grill. Cook for about 10-12 minutes, turning occasionally, until the chicken is cooked through and has nice grill marks. The internal temperature should reach 165°F (74°C).
When the skewers are done, remove them from the grill and let them rest for a couple of minutes.
Arrange the skewers on a serving platter and garnish with fresh cilantro leaves for a burst of color and flavor.