Trim leaves and bottom stalk from cauliflower, making sure not to remove the core. Place cauliflower in Round Steamer. Cover; microwave on high 5–6 min or until a knife can easily slide into it.
Meanwhile, cut each tofu block in half, lengthwise. You should have four pieces. Pat dry with a paper or kitchen towel.
Whisk together water, maple syrup, oil, and seasoning. Brush sauce on one side of tofu steaks. Place on grill, saucy side down. Brush sauce on top. Grill with lid closed for 10 min, flipping once, until lightly charred.
Brush the remaining sauce all over cauliflower. Place on grill, florets side down. Grill 5 min, then flip and cook 2 more min.
To serve, slice cauliflower into steaks or wedges. Top cauliflower and tofu with yogurt, and additional toppings, if desired.