Step 1

Add the olive oil, water, egg and salt, mix and form a ball.

Step 2

Wash the tomato, remove the stalk and cut it into small cubes.

Step 3

Wash the cucumber then cut it into small dices.

Step 4

Wash and hull the radishes, then cut them into thin rings.

Step 5

Coarsely mash the drained tuna with a fork.

Step 6

Peel and cut the avocado into thin slices. Drizzle them with lemon juice to prevent oxidation.

Step 7

Wash and wring out the spinach leaves.

Step 8

Divide all the ingredients evenly among bowls.

Step 9

Prepare the sauce: mix the Dijon mustard, the Swiss cheese, a small pinch of salt and pepper. Drizzle the bowls with the sauce then serve immediately.