I suppose it depends on the buget, buy fresh.
Tuna salads with some boiled pasta, easy to make at your own taste.
Add some garlic in the tuna, in a pan with a little cream and some fine chopped mushrooms.
Can serve on top of a pasta, or even good rice, heat later on in micro, great taste and a good lunch with a bread roll.
Canned sardines, (YES) and also served with a light salad and brown toast.
All poured over the toast.
Cooked ham in lightly made sandwich of good healthy bread, use thin ham.
A prepared meatball and speg sauce, easy to heat in a micro.
Prepare the night before and take along to share with some friends who have a micro.
Pack in micro tight dishes.and bring along a parmo shaker.
A simple two egg om, stuffed with a little ham, mushrooms, small sliced onion and cooked in a little olive oil served on top of some good old lettuce.
Last but not least.
A nice piece of boiled chicken,go for leg and thigh and remove skin.
Serve on a bed of rice with egg noodle and add some soya sauce for a great taste.
Keep pasta and rice in the house and after that you just need to think what will go with them.
Iff all above fails, stay away from the big macs and so on.
Go for a lightly made pizza, the veg type.
Good luck and enjoy.