Marinade: Squeeze the juice of lemons into a sealable plastic bag, take out any seeds, add 3 clove garlic minced, oregano, and olive oil. Cut chicken into 1-inch cubes and place in bag with marinade. Close and set in fridge overnight, until ready to assemble skewers and cook.
Rinse and cut vegetables into 1-inch square slices: zucchini, bell pepper, and red onion. Rotate marinaded cut chicken cubes and vegetables on skewers.
Grill for 12-15 minutes, turning throughout cooking time until juices run clear. These Kabobs can also be made in the oven at 450, 10-15 minutes on one side, turn then on the other.