Wash and dry all produce. Drain and rinse black beans. Halve, peel, and dice onion. Drain half the corn from the can (use the rest as you like). Core, seed, and dice tomato. Halve lime; cut one half into wedges. Mince jalapeño, removing ribs and seeds for less heat.

Halve, pit, and scoop flesh from avocado, then cut into 1/2-inch cubes. In a medium bowl, toss together avocado, 2 TBSP of the onion, a quarter of the tomato, and up to half the jalapeño (use less to taste). Stir in a squeeze of lime. Season with salt and pepper.

Heat a drizzle of olive oil in a large pan over medium heat. Add remaining onion and jalapeño (to taste). Cook, tossing, until softened, 2-3 minutes. Stir in corn, black beans, cumin, and remaining tomato. Add a pinch of cayenne pepper (to taste). Cook, tossing, until tomato has softened, 4-6 minutes. Season with salt and pepper.

Transfer bean mixture to a large bowl. Mash with a potato masher or fork until mostly smooth. Stir in 3 TBSP panko (we sent more). Season with salt and pepper. Place remaining panko on a plate or in a wide, shallow bowl. Shape bean mixture into 2-inch-wide patties and press into panko to adhere.

Wipe out same pan with a paper towel, then heat a drizzle of olive oil in it over medium heat. Add bean cakes to pan. Cook until browned on surface, 2-3 minutes per side. Season with salt and pepper.

In a medium bowl, toss arugula, a drizzle of olive oil, and 1 TBSP balsamic vinegar (we sent more). Season with salt and pepper. Divide arugula between plates, then top with bean cakes. Scatter avocado salsa on top and dollop with sour cream. Serve with lime wedges on the side for squeezing over.