Ask your kind fishmonger to clean the calamari and remove the soft bone from the inside. Cut the calamari in 7-8 mm thickness and the tentacles in 2-3 pieces and pat dry with kitchen towel.
In a medium pot on high heat bring Kirtamo water to the boil. Add the Kritamo and once boiling cook for further 90 seconds. Remove from heat to a bowl full of cold water and some ice cubes. Drain and place in a bowl, toss with a pinch of salt and keep aside.
Put a large saucepan or pot on medium-high heat and when hot pour 3 tablespoons of oil. After a minute add the yellow onion and the Mousoules and sauté for 4-5 minutes until slightly coloured.
Increase the heat and add the large calamari, continuing sautéing for 4-5 minutes until they get a nice light gold color but not overcooked. Add the orzo and sauté for a minute stirring continuously and deglaze with the wine. Let the alcohol evaporate, 2-3 minutes. Add the tomatoes and tomato paste and stir well.
Reduce the heat to medium and start adding the stock 1 cup at a time, in the same manner as in when cooking risotto. Keep on stirring and once the water has been almost absorbed add the next 2 cups of stock.
Repeat process until all stock has been used and then add the Kirtamo along with the lemon juice and zest and season with the salt and pepper. Mix well and serve in a flat dish.
In the meantime, in a small non-stick saucepan add 2 tablespoons of olive oil on medium heat. Wait a minute to heat up and add the small calamari uncut. Sauté for 4-5 minutes, turning and tossing couple of times until slightly golden in colour. Serve on top of the Kritharotto.