At one of the places I worked they used to make this at the cafeteria once a week -- I think they called it "Mexican Sunrise." I made it last night and I had forgotten how great it was.
Slice half of an orange sweet potato the long way to make 2 quarters (or a whole small one in half) -- about 200g or 150-200 calories worth. Toss or brush with 1/2 tsp olive oil, and salt and pepper.
Broil, grill or bake potato at 450 degrees for about 25 min until outside is crispy and browned.
Top with —
1/2 cup black beans (100 cal)
1 tbsp shredded cheese (50 cal)
(I use the premixed Kraft "Mexican" mix which I think is cheddar and colby.) Put back in oven for 5 minutes or so until cheese is melted.
Top with salsa and a tablespoon of thick yogurt if desired. Can add a couple of grilled shrimp or fake crabs for more color, and a green salad on the side.