Heat cooking oil in pan.  Then sauté thin strips of onion, pineapple (use a little bit of juice), mandarin oranges, chicken or beef.  For celery cut diagonally.  Can also add broccoli, peppers, mushrooms, zucchini, squash.  Different seasoning options include garlic, ginger, soy sauce, season salt. Can thicken sauce with cornstarch. Put in tomatoes very last.