These bagels make a great quick dinner, and if you're really pressed for time, you can simply leave out some of the ingredients other than the basics - the tuna, bagels, mayo, onions and cheese.
1 (7 oz) can chunk tuna, drained and flaked
1/3 cup mayonnaise
1/3 cup sun-dried tomato pesto
1/2 cup diced celery
2 green onions, chopped
1/4 cup chopped dill pickle
2 tbsp chopped parsley
2 bagels, cut in half crosswise
1/4 cup grated Parmesan cheese
salt and pepper, to taste