I never even thought about grilling it.
1 14-16 ounce container extra-firm tofu
3/4 cup Sriracha
1 tablespoon roasted sesame seeds plus more
1 tablespoon soy sauce
1 tablespoon white miso paste
3 chopped scallions plus more
2 garlic cloves
Cut tofu into 1" blocks. Drain well on paper towels.
Put Sriracha, 1 tablespoon sesame seeds, soy sauce, and white miso paste in a blender with 3 chopped scallions and garlic cloves. Blend with water until smooth. Reserve a cupful for dipping; marinate the tofu in the rest overnight.
Shake off excess sauce and grill tofu, brushing with sauce. Sprinkle with roasted sesame seeds and scallions.