In a small saucepan, combine the Mountain Dew, tamari, honey, minced ginger, and minced garlic.
Simmer the mixture over medium-low heat for 10 to 12 minutes until it reduces into a thick, syrupy glaze.
While the glaze reduces, cut the chicken breast, bell peppers, and red onion into uniform 1-inch cubes.
Thread the chicken and vegetables onto skewers, alternating pieces to ensure even cooking.
Brush the skewers lightly with olive oil and season all sides with sea salt and black pepper.
Preheat a grill or grill pan to medium-high heat and lightly oil the grates.
Grill the skewers for 4 to 5 minutes per side, brushing generously with the soda glaze during the final 3 minutes of cooking.
Remove from the heat once the chicken reaches an internal temperature of 165 degrees Fahrenheit and the glaze is bubbly and caramelized.