For the salsa verde: Chop the parsley, capers, anchovies and garlic by hand, and then toss with the oil, some pepper and the lemon juice in a bowl. Alternatively, add the parsley, capers, anchovies, garlic, oil, some pepper and the lemon juice to a food processor and chop and combine. Transfer to the refrigerator. It can be kept refrigerated and covered for up to 3 days.
For the tuna: Mix together the oil, some salt and pepper, the tuna and lemon juice and zest in a bowl. Stir with a fork to combine. Season, keeping in mind that the salsa verde will be salty, so the tuna should not be overly seasoned. Divide the tuna salad among the rolls, top with slices of tomato and spoon on the salsa verde. Serve and enjoy.