In a large bowl, mix together 110 g Tuna, 1 rib Celery, 0.25 Cucumber, 2 Spring onion (Scallion), 2 Gherkins and 4 tablespoon Sweetcorn.
Mix in2 tablespoon Light mayonnaise, juice of 0.5 Lemon and 1 pinch Sea salt and ground black pepper.
On two of the 4 slices Sourdough bread, add the tuna mix.
Top with 1 Beef tomato (sliced), 100 g Rocket (arugula) and the second slice of bread.
Notes
Why not try adding some avocado for a little bit of extra creaminess or some chopped jalapenos if you like things spicy. You could add a drizzle of Sriracha too.
If you want to save some calories with this sandwich, swap the mayo for Greek yoghurt, or go half and half.
You can add some extra flavour with a teaspoon of dijon mustard and some chopped fresh parsley or dill.
If you don't like tuna, try making this with leftover shredded chicken.
Swap the slices or bread for a bagel, or try putting it on a croissant.
If you want a low carb version of this, put the filling in to half an avocado (that has had a little scooped out, then pile the filling up) or on a salad.
Leftovers of the filling will keep in the fridge in an airtight container for 2 days.