Tofu: Press tofu dry with paper towels and slice in half through the middle to form two thin slabs. In a shallow container large enough to fit the tofu, stir together oil, soy, garlic powder, and paprika, then add tofu slabs. Cover tofu with the marinade and let soak for 15 minutes while you heat up the grill.
Prep: Cut romaine heads in half lengthwise. Combine oil and lemon juice, and liberally brush onto the romaine and corn. Cut tomatoes, crumble feta, and mix together kefir ranch dressing if using.