Marinate the chicken breast pieces in the lemon juice, lemon zest, and pepper for 30 min- 1 hr.
Cut the red onion in triangles (like you cut a pie). You will use 3 layers at a time.
Add chicken, bell pepper, tomatoes, and red onion to skewers in a pattern until each skewer is full and you're out of ingredients.
Either set on a grill, in a grill press, or on a pan on the stove. Cook for a few minutes on each side until the chicken is cooked and everything is charred. Top with more cracked black pepper. Enjoy!