Cubes of tuna coated in a mustard dressing are grilled with marinated baby artichokes. The baby artichokes are cooked in advance so they only need to be grilled for a short time.
Whisk together mustard, lemon juice, red-pepper flakes, 6 tablespoons olive oil, and garlic in a large bowl. Add tuna, and toss to coat.
Thread 4 cubes of tuna, alternating with artichokes, on each of 8 skewers. Gently brush with some of the remaining olive oil. Season with salt and pepper.
Arrange skewers, off direct heat, on a medium-hot grill. Grill, rotating skewers and brushing with olive oil as necessary to prevent sticking, until tuna is brown and charred on the outside and warm but still rare in the middle, about 5 minutes, depending on heat of grill. Artichokes should be tender and slightly charred. Serve with choice of condiments.