Cook rice in large pot of boiling salted water until al dente, 25-30 min.
Drain and rinse.
Place in a large bowl, toss with beans, set aside.
Oil the grill rack using a paper towel (do not use cooking spray over a hot grill).
Grill corn, onions, and bell pepper, turning frequently, until tender and charred (10-12 min.).
Cut kernels from cobs and add to reserved rice and beans.
Dice the bell pepper and half the onions.
Add to rice mixture.
Place the remaining onions in a mixing bowl.
Peel and dice avocado and add half to rice mix and half to bowl of onions.
Whisk salsa, orange juice, lime juice, cilantro, oil and cumin in small bowl.
Season with salt and pepper.
Toss 3 Tablespoons of salsa mixture with sliced onions and avocado.
Toss the rest with rice mix.
Spoon rice mixture onto a serving dish and top with onion-avocado mixture.
Serve with chips.