Preheat oven to 450F. Pierce potatoes with a knife or fork in several different places. Bake for about 50 minutes, or until soft throughout. While the potatoes are baking, prepare the stuffing.
Prepare the Salsa: Dice the tomatoes and red onion, transfer to a medium bowl. Chop cilantro, then add 3 tbsp. of cilantro to the bowl, set the rest aside for later. Squeeze lime juice into the bowl. Season to taste with salt and pepper. Mix until thoroughly combined. Set aside.
Prepare the Guacamole. Scoop avocado into a separate medium bowl. Mash well, then add onion powder, garlic powder and 1/3 of the homemade salsa. Add salt and pepper. Mix well, set aside.
In a separate microwave safe bowl, heat frozen corn in the microwave for about 2 minutes. Remove from microwave, then add in black beans and 1/2 of the remaining salsa mixture. Season with salt and pepper. Mix well, set aside.
Remove potatoes from oven and let sit until just cool enough to handle. Slice potatoes in half, stopping about 1/2 way through so the bottom portion of the potato is still in tact (this will keep things from getting too messy and make the potato itself a sort of bowl to hold the stuffing without falling apart). Mash the center of each potato with a fork.
Stuff baked sweet potato with black bean mixture, followed by salsa, then guacamole. Top with green onions and remaining cilantro. Serve with a lime wedge on the side.