To make the tuna conserva, on medium heat, bring the oil up to a simmer with the garlic, orange, lemon, and bay. Meanwhile season the tuna with the spices. Add the tuna to the oil and remove from the heat. Let come to room temperature and then refrigerate. The fish should be just cooked through.
To make the red "winette," in a small sauce pan on medium high heat, reduce the vinegar, wine, and shallot by 1/2. Let cool and whisk in the extra virgin olive oil. Season to taste with salt and pepper.
To make the croutons, preheat the oven to 375. Squeeze the croutons, to remove any excess milk. Toss in olive oil, salt and pepper, and bake on a baking sheet until golden, about 10 minutes.
Toss the croutons with the tomato, cucumber, arugula, and red "winette." Arrange on the plates, top with pieces of the tuna and drizzle with a little extra "red winette." Sprinkle olives about.