Fennel-Crusted Ahi Tuna with Lemon Aïoli Over Couscous

Ingredients

• 2.5 pounds ahi tuna steak thick ()
• 1 teaspoon peppercorns whole black
• 1  carrots peeled coarsely chopped
• 1 teaspoon coriander seeds 
• 2 cups couscous 
• 2 teaspoons fennel seeds 
• 3 tablespoons chives fresh chopped
• 2 tablespoons optional: dill fresh chopped
• 2 teaspoons thyme sprigs fresh chopped
• 4  garlic clove divided minced
• 1.5 teaspoons kosher salt divided
• 2 tablespoons juice of lemon fresh
• 0.3 cup mayonnaise 
• 0.5 cup olive oil extra virgin extra-virgin divided
• 0.3 cup onion red chopped
• 0.5 pound sugar snap peas 
• 2.3 cups water 

Equipment

• bowl
• frying pan
• whisk
• grill
• slotted spoon

Directions

1. Combine first 3 ingredients in heavy small skillet. Toast over medium heat until fragrant, shaking skillet occasionally, about 3 minutes. Grind spice mixture in spice grinder.
2. Transfer to bowl; mix in 1 teaspoon salt.
3. Whisk mayonnaise, lemon juice, chives, and half of garlic in small bowl. (Can be made 2 days ahead. Store spice mixture airtight at room temperature. Cover and refrigerate lemon aioli.)
4. Heat 2 tablespoons oil in heavy large skillet over medium-high heat.
5. Add carrot and onion and sauté until crisp-tender, about 3 minutes.
6. Add thyme and remaining garlic and sauté 1 minute.
7. Add 2 1/4 cups water and remaining 1/2 teaspoon salt; bring to boil.
8. Add sugar snap peas and cook until crisp-tender, about 1 minute. Using slotted spoon, transfer peas to plate. Immediately add couscous to water in skillet and stir to combine. Cover and remove from heat.
9. Let stand 5 minutes. Fluff couscous with fork.
10. Transfer to bowl and cool completely.
11. Mix in sugar snap peas and dill. Season to taste with pepper. (Couscous can be made 2 hours ahead.
12. Let stand at room temperature.)
13. Prepare barbecue (high heat). Coat tuna with 6 tablespoons oil.
14. Sprinkle with spice mixture. Grill tuna until seared outside and rare in center, about 4 minutes per side. Refrigerate uncovered for 1 hour, then cut into 1/2-inch-thick slices. Spoon couscous onto plates. Top with tuna and drizzle with lemon aioli.