1. In 4 resealable bowls that fit in the lunchbox, distribute the lettuce, then the green beans, onion, and hard-boiled eggs. Crumble the mackerel fillets over top of each salad. Add tomatoes, capers, olives, parsley, and croutons. 
2. In small bowl, whisk together the anchovy paste, lemon juice and zest. Whisking continuously, add remaining ingredients. Divide into 4 small, resealable containers for the lunchbox. Refrigerate until ready to serve. 

Family tip: You can use canned tuna or salmon, or even leftover chicken. 

Sporting tip: Add an extra hard-boiled egg for each serving. 

Vegetarian tip: Omit the anchovy paste and replace the mackerel in the salad with a vegetarian cutlet or veggie burger patty. 

Time saving tip: Frozen beans are a good substitute, and so is commercial Caesar dressing.