Add the rice to a pot and cover with one and one fifth cups of water. Bring to a boil over high heat then reduce to low and cook until the water is absorbed and the rice is tender. Stir in half a teaspoon of salt, a tablespoon of lemon or lime juice, and quarter cup of chopped parsley or cilantro. Fluff with a fork and set aside.

Heat a large skillet over high heat and add a tablespoon of olive oil. Add the frozen corn and sauté without stirring constantly until the kernels develop light browning and a sweet aroma. Transfer the corn to a bowl and leave the skillet in place for the next step.

Lower the skillet heat to medium and add the chopped onion with a splash of olive oil if needed. Sauté briefly until the onion begins to soften. Add the chili powder and a half teaspoon of salt, and let the spices warm for a few seconds to release their aroma. Add the drained and rinsed black beans and stir gently until the beans are warmed through. Turn off the heat.

Wash and chop the romaine lettuce into bite sized pieces. Halve the grape tomatoes. Cut the avocado into slices or cubes and squeeze a little lemon or lime over the surface to keep it fresh. Prepare pickled red onions or thinly slice raw red onion for topping.

Assemble each bowl by layering lettuce, rice, black beans, sautéed corn, salsa, grape tomatoes, avocado, and pickled or raw red onion. Finish with an extra pinch of salt, a sprinkle of chili powder if desired, and an additional squeeze of lemon or lime to brighten. Serve immediately or pack components separately for later assembly.