For the grilled vegetables:
Preheat the oven to 300°F. Prepare a charcoal or wood fire and let it burn down to embers, and lightly oil a clean grill rack.
Lightly grease 2 baking sheets with vegetable oil.
Drizzle the tomatoes with 1 tablespoon of the olive oil and sprinkle with cumin and curry powder. Place on a prepared baking sheet and roast until softened and somewhat shrunken, about 40 minutes.
Rub the fennel with olive oil, season with salt and pepper, and grill just until marked on both sides. Drizzle the leeks with another tablespoon of olive oil and season with salt and pepper. Place the fennel and leeks on a prepared baking sheet, season, and bake until soft, about 15 minutes.
While the fennel and leeks are baking, rub the zucchini and yellow squash with the remaining tablespoon of olive oil, season with salt and pepper, and grill until marked on both sides and tender, 1 to 2 minutes per side.
For the tuna:
Season the fish with salt and pepper and place on the oiled grill rack. Cook until golden brown, about 5 minutes. Turn and cook until done, 3 to 4 minutes more.
Divide the grilled vegetables and roasted tomatoes among 4 serving plates. Arrange a portion of fish on top and drizzle with the vinaigrette.
For grilled vegetables, substitute Ratatouille or Confit Bayaldi.
For tuna, substitute bass or cod.
Serve grilled vegetables with:
Any seared and roasted fish
Seared and Roasted Chicken Breasts
Simple Roasted Chicken
Saddle of Lamb, instead of Ratatouille
Double-cut lamb chops
Drizzle with a little Basil Oil