Preheat grill to 350° to 400° (medium-high) heat. Coat corn, jalapeño pepper, onion, and cut sides of tomatoes lightly with cooking spray. Grill corn and onion, covered with grill lid, 15 minutes or until golden brown, turning occasionally. At the same time, grill tomatoes and jalapeño pepper, covered with grill lid, 8 minutes or until grill marks appear, turning occasionally. Remove all from grill, and cool 15 minutes. Cut corn kernels from cobs; discard cobs. Coarsely chop onion.
Pulse garlic and next 2 ingredients in a food processor until finely chopped. Add grilled tomatoes, onion, and jalapeño pepper to food processor, in batches, and pulse each batch until well blended. Transfer to a large bowl. Stir in salt and corn. Serve with pork rinds.