Okinawan Taco Rice

Ingredients

• 2 cups sushi rice
• 3½ cups water, divided
• 2 tablespoons vegetable oil
• 1 onion, chopped fine
• 1 pound 90 percent lean ground beef
• 1 (1-ounce) packet taco seasoning
• 2 tablespoons ketchup
• 2 tablespoons mirin
• 2 tablespoons soy sauce
• 1 teaspoon Hondashi instant dashi
• 4 ounces Monterey Jack cheese, shredded (1 cup)
• 2 cups shredded iceberg lettuce
• 1 avocado, halved, pitted, and cut into ½-inch pieces (optional)
• ½ cup jarred tomato salsa
• Lime wedges