Pat the tofu dry with a paper towel and then cut into 1/2-inch cubes.
In a large bowl, combine the tofu cubes, garlic, sesame oil, soy sauce, orange juice and the juice of 2 limes. Give it a good stir, then cover with plastic wrap and let marinate in the refrigerator for at least 30 minutes or as long as overnight.
Mix together the sour cream, sriracha and the juice of 1 lime in a small mixing bowl. Cover with plastic wrap and refrigerate until ready to serve.
Heat the vegetable oil in a large saute pan over medium heat. Fry the tortillas in batches of two until lightly crispy but still tender on the inside, 1 to 2 minutes per side. Drain on a paper-towel-lined plate.
Remove the tofu from the marinade and pat dry with paper towels. In the same pan the tortillas were cooked in, sear the tofu over medium-high heat until browned on all sides, 6 to 8 minutes. Remove to a paper-towel-lined plate.
Add the cabbage to the pan and saute until wilted, 3 minutes. Add the spinach and saute until wilted, another 2 minutes. Season to taste with salt and pepper.
Spread each tortilla with a spoonful of the sour cream mixture. Top with the spinach and cabbage and 4 or 5 crispy tofu cubes. Serve immediately.