Cook Beef Mixture: Heat oil in a large skillet over medium-high heat. Add beef and break it up, then add the garlic, ginger, onion, and red pepper. Cook until beef is no longer pink and vegetables are cooked. Stir in the 1-2 tablespoons Sriracha and salt to taste.
Make Sriracha Sauce Topping: while beef and vegetables are cooking, mix all the topping ingredients in a bowl and whisk until smooth. If needed, add a bit of water to thin to pouring consistency.
Assemble Bowls: divide spinach between 4 bowls and top each with 1/2 cup of rice and a 1/4 of the beef mixture. Arrange the carrots and cabbage over the bowls. Drizzle some of the Sriracha sauce topping over all, leaving some to serve at the table. Garnish with green onions and sesame seeds if desired.
Notes
*You can make this sauce more spicy by using up to 1/4 cup Sriracha. Start with the smaller amount and level up as you like.Variations: You can use any ground meat or even leftover shredded meat as well as other raw vegetables.