Begin by preparing your chicken: chop the chicken breasts into even 1-inch cubes, ensuring uniform size for even cooking.
In a small bowl, whisk together olive oil, lemon juice, paprika, cumin, and garlic powder to create a flavorful marinade.
Place the chicken cubes in a large bowl or zip-top bag, then pour the marinade over the meat. Toss gently to coat all pieces evenly, then cover and refrigerate for at least 30 minutes to allow the flavors to meld.
While the chicken marinates, prepare the vegetables: chop bell peppers and red onion into chunks roughly the same size as the chicken cubes.
Once marinated, thread the chicken pieces onto skewers, alternating with pieces of bell peppers and onions for a colorful presentation. Keep the pieces snug but not too tight to allow even cooking.
Preheat your grill to medium-high heat until hot and slightly smoky, ensuring a steady sizzle when the kabobs are placed on the grates.
Carefully place the skewers onto the grill, spacing them apart to allow heat circulation. Close the lid and cook for about 7-8 minutes, turning every 2-3 minutes to develop an even char and smoky aroma.
As the kabobs grill, listen for the satisfying crackle of the marinade and the gentle sizzle of the chicken searing, with occasional popping as juices escape.
Once the chicken is golden brown and cooked through (internal temperature of 165°F), remove the skewers from the grill and let rest for a few minutes.
Serve the kabobs hot off the grill, with a squeeze of fresh lemon if desired, and enjoy the tender, smoky flavors with the colorful vegetables providing crunch and sweetness.