Adjust rack to top position (top and middle positions for 4 servings) and preheat oven to 425 degrees. Wash and dry produce.

Drain beans. Drain corn. Core, deseed, and dice bell pepper into ½-inch pieces. Halve, peel, and dice onion. Quarter lime. Dice tomato. Roughly chop cilantro.

Toss beans, corn, bell pepper, and half the onion on one side of a baking sheet with a large drizzle of olive oil, garlic powder, half the Mexican Spice Blend, salt, and pepper. (For 4 servings, spread veggies out across entire sheet.) Roast on top rack until veggies just begin to soften, 9-11 minutes (you'll add tilapia to the sheet then!).

Meanwhile, in a small bowl (medium bowl for 4), combine juice from half the lime with as much remaining onion as you like. TIP: This will help soften the sharp flavor of raw onion.

Pat tilapia* dry with paper towels. Lightly drizzle with olive oil; season with remaining Mexican Spice Blend, salt, and pepper.

Once veggies have roasted 9-11 minutes, lightly drizzle empty side of sheet with olive oil; carefully add tilapia. Roast on top rack until veggies are tender and fish is cooked through, 8-11 minutes more. (For 4 servings, leave veggies roasting; arrange tilapia on a second baking sheet and roast on top rack.)

While fish and veggies roast, add tomato, cilantro, salt, and pepper to bowl with onion. Stir to combine.

Divide black bean jumble between plates; top with tilapia. Top with a squeeze of lime, guacamole, and pico (draining first). Serve.