Cook the risoni in a saucepan of boiling, salted water according to packet directions. Drain and rinse under cold water.
Meanwhile, combine the ricotta, chopped basil and 1 tablespoon of the olive oil in a small bowl. Season to taste.
Combine the cooked pasta, basil leaves, capers, tomato, rocket leaves, lemon juice and remaining tablespoon of olive oil in a large bowl. Gently mix through large chunks of tuna, being careful not to break them up too much.
Serve topped with a spoonful of the ricotta.
