To make the marinade, whisk together the soy sauce and tomato sauce in a bowl.

Add the thyme leaves, green onions, and black pepper, and mix well. Add the chicken to the marinade, and stir to make sure every piece is covered.

Cover the bowl with plastic wrap and put it in the fridge for at least one hour.

When the grill is hot, thread the chicken onto the pre-soaked wooden skewers and cook them on the grill. Halfway through cooking, turn them over and brush them with the remaining marinade.

When the chicken has reached an internal temperature of 165F, serve and enjoy!