Pre-heat your barbecue to medium-high heat.
Using a small spoon, scoop the gills out of the mushrooms.
Brush mushroom exteriors with olive oil and place on a large plate.
In a medium bowl, whisk together the enchilada sauce, salt and flour until no lumps remain.
Spoon around 2 tablespoons of corn and black beans into each mushroom. Drizzle with the sauce. Top with shredded cheese.
Grill over direct heat (on a veggie grilling plate, or directly on clean grill) for 5-6 minutes, until cheese is melted and sauce is bubbling.
Sprinkle with chives and serve with a side salad.