Ahi Tuna BLTs

Ingredients

• 2 tbsp mayonnaise
• 1 tbsp prepared horseradish
• Pinch salt
• Pinch freshly ground pepper
• 1 tsp canola oil
• 1/4 cup sliced shallot
• 1 clove garlic, finely chopped
• 8 cherry tomatoes, halved
• 1 tsp packed golden brown sugar
• Salt and freshly ground pepper*
• 1 tsp caraway seed
• 1 tsp fennel seed, crushed
• 1/2 tsp freshly ground pepper
• 1/2 tsp salt
• 1/2 tsp red pepper flakes
• 1 lb (0.5 kg) sushi-grade ahi tuna fillets, 1 inch thick
• 4 slices thick bacon, halved crosswise
• 4 hamburger buns
• 1 cup baby arugula