Mix together the chili powder, paprika, and cumin in a small bowl until well combined.
Add the olive oil to a skillet over medium heat on the stove.
Place the tofu pieces in the heated skillet, then season both sides with the spice mixture plus salt and pepper to taste. Cook for several minutes on each side until crispy, then remove and set aside.
Place 2 cups of lettuce in each of the four bowls.
Divide the tofu, rice, corn, and beans evenly between each bowl.
Top each bowl with ¼ of the chopped tomato and a serving of guacamole. Serve with salsa if desired.