Prep the marinade: In a large bowl, whisk together olive oil, lemon juice, garlic, honey, soy sauce, smoked paprika, oregano, cumin, red pepper flakes, 1.5 teaspoons salt, and 1/2 teaspoon black pepper.
Marinate the chicken: Add the chicken cubes and toss to coat.
Cover and refrigerate for at least 30 minutes and up to 4 hours. Longer than 4 hours isn’t necessary because of the lemon juice.
Prep the vegetables: Cut peppers, onion, and squash into even pieces. Pat them dry and toss with a little olive oil, a pinch of salt, and pepper.
Preheat the grill: Heat a gas or charcoal grill to medium-high (about 400–450°F).
Clean and oil the grates to prevent sticking.
Build the kabobs: Thread chicken and vegetables onto skewers, alternating for color and even cooking. Don’t pack them too tightly; a little space helps them sear instead of steam.
Grill: Place kabobs on the grill. Cook for 10–12 minutes, turning every 3–4 minutes, until the chicken is lightly charred and cooked through.
Internal temperature should reach 165°F.
Finish: Move kabobs to a cooler zone for a minute to rest. Squeeze fresh lemon over the top and sprinkle with parsley or cilantro.
Serve: Pair with rice, couscous, warm pita, or a crisp salad. Offer extra lemon wedges and your favorite sauce.