Grilled Halibut with Tatsoi and Spicy Thai Chiles

Name: Grilled Halibut with Tatsoi and Spicy Thai Chiles
Ingredients: 5 tablespoons sugar; 5 tablespoons fish sauce*; 1/4 cup water; 3 tablespoons fresh lime juice; 2 tablespoons minced peeled fresh ginger; 2 garlic cloves, minced; 2 Thai bird chiles with seeds or 1/2 large jalapeño chile with seeds, minced; 1 small carrot, peeled, cut into matchstick-size strips; 4 6- to 7-ounce halibut fillets; 3 tablespoons vegetable oil, divided; 1 shallot, thinly sliced; 3/4 pound tatsoi or baby spinach (about 12 cups packed)