Coriander crusted seared ahi tuna

Ingredients

• 1 c champagne vinegar
• 1 cup water
• 1 tsp coriander
• 1 tsp peppercorns
• 2/3 c sugar
• 2/3 c salt
• 4-5 red pearl onions peeled
• 4-5 baby carrots
• 1 sliced jalapeño
• Mache
• Picked cilantro
• 2 tbs coriander
• 1 6 oz log of tuna lion