Preheat broiler to high or preheat outdoor grill.

Prepare tuna: Place tuna steak on a plate.

Season tuna with salt and pepper on both sides.

Brush tuna with a mixture of 1 tablespoon olive oil and thyme.

Cover tuna closely with plastic wrap and let stand until ready to broil or grill.

Broil tuna: Arrange tuna steak on a rack about 6 inches from the heat source if broiling.

Broil for 4 minutes with the door partly open.

Turn tuna steak and continue broiling for about 4 minutes more, leaving the door open.

Grill tuna: Place tuna steak on a hot grill and cover if grilling.

Cook for 4 minutes.

Turn fish, cover the grill, and cook for about 4 minutes more.

Remove fish and let it cool.

Prepare couscous: Heat 1 tablespoon olive oil in a small saucepan.

Add finely chopped onion, finely chopped garlic, and ground cumin.

Cook, stirring, until vegetables are wilted.

Add water, salt, and pepper.

Bring to a boil and add couscous, stirring.

Cover closely.

Remove from heat and let stand for 5 minutes.

Put couscous in a bowl to cool.

Prepare salad dressing: Combine red-wine vinegar, 6 tablespoons olive oil, soy sauce, chopped jalapeno pepper, Tabasco sauce, diced celery, diced tomatoes, minced garlic, chopped fresh basil, lemon juice, and grated orange rind in a large bowl.

Blend well with a wire whisk.

Check for seasoning.

Cut tuna into bite-size pieces and add to the couscous in the bowl.

Pour dressing over all and toss well.

Serve immediately.