One of the easiest quick meals, snacks or work lunch you can make is tuna and pasta using a flavoured tuna tin.
My choice of tuna flavour is tomato and onion.
For 1 person all you need is a handful or two of cooked pasta, a small tin of your mostly drained favourite flavoured tuna, a handful of grated cheese and some optional fresh chopped parsley.
Put all together in a microwave dish and zap until cheese is melted and heated through maybe 20-30 seconds. Eat.
For a work lunch this can be popped into a lidded container the night before ready to go the next day.
If you want a bigger more rounded meal add some cooked frozen peas and corn into the mix.