A good way to do this is choose a complimentary color for the kitchen and extent this color into the dining room, stopping at the nearest true corner. The kitchen color becomes an accent for the dining room.
This is the best way to separate the two rooms without making a straight line. Alternatives include building a small false wall (12 inches wide from floor to ceiling) or extending cabinets or a back splash to a natural breaking point between the rooms. Also, a piece of wood trim could be used to cover the line, but needs to be repeated on the opposite wall for continuity.