Preheat the oven to 220C (425F).
In a large bowl, combine the oil with half of the miso granules, rice vinegar, soy sauce, maple syrup, sriracha, and garlic powder. Add the cauliflower. Add black pepper and stir.
Spread the mixture onto a baking tray lined with parchment paper. Cook in the oven for 18 to 20 minutes, flipping halfway through.
Turn the oven to the grill (broil) setting and cook for 2 to 4 more minutes, until the cauliflower florets are charred. Remove from the oven and let it cool.
Meanwhile, combine the ingredients for the sauce in a bowl.
Garnish the cauliflower bites with coriander and the rest of the miso granules. Serve with lime wedges and the sauce.