Pan Bagnat with Radish and Tuna

Name: Pan Bagnat with Radish and Tuna
Ingredients: 1 On loaf of French bread, a baguette or a batard wide enough to contain this mess; 1 to 2 cans of tuna packed in olive oil (this matters—I use As Do Mar or Ortiz), about 150 grams in total weight; 2 to 3 really good anchovy filets (don’t wimp out on me); 1 sweet onion, such as Vidalia or Walla Walla; 1 fresh, vine ripened tomato; 1 bunch basil or substitute watercress; 5 radishes, French breakfast radishes preferred; 1 handful of Nicoise olives, pitted and sliced; Your best olive oil*