Start by cleaning the crab. See instructional video in the article above, cut into medium pieces. You want to be able to see the crab pieces, so don't cut the crab too small.
Next peel and de-vein Shrimp, chop into medium-small pieces. ( You could Cook the shrimp part-way in butter & garlic before stuffing and combining all ingredients ) Crab - do not pre-cook ))
The tomatoes need to be cored. Keep the tops for garnish. Use a spoon and scoop out the pulp. Turn them upside down while chopping the rest of the ingredients allowing the tomatoes to drain the extra water out.
Cut the corn off the cob using a bundt pan if you have one. Next, chop the corn into small pieces. Think about each kernel being cut into thirds.
Dice bell pepper - small dice cut, Mince onion, chop cilantro.
Combine all vegetables first, combine well. Then add the shrimp and crab being careful to not break up the crab much more than it is. Add the seasoning, plus the ranch dressing and combine, then fill the tomatoes. Salt the insides of the tomatoes before filling. Top with cheese like parmesan or top with breadcrumbs.