1. Mix oil, water, mustard, salt, and pepper in a container.
2. Cut the chicken breasts into cubes.
3. Place them in a shallow dish and pour the oil-mustard mixture over them.
4. Let marinate in the refrigerator for an hour, mixing regularly.
5. Cut the pineapple slices into cubes.
6. Clean, remove seeds, remove filaments, and cut the red pepper into pieces.
7. Thread the marinated chicken, pineapple, and pepper onto wooden skewers, alternating them.
8. Grill the skewers on the barbecue for about 15 minutes, until all sides of the chicken are golden brown.
9. Serve hot with a homemade spicy sauce.