How to Make It
Preheat grill to medium (about 450°F). Toss together the scallops, olive oil, black pepper, and 1/2 teaspoon of the salt in a large bowl until scallops are evenly coated; chill until ready to use.
Grill the corn, scallions, and jalapeños, turning often, until charred and tender and the corn begins to release its juices, 5 to 7 minutes. Remove from grill; cool 5 minutes.
Cut corn kernels from cobs into a medium bowl; discard cobs. Finely chop the scallions; add to the corn kernels. Remove stems and seeds from the jalapeños. Finely chop jalapeños, and add to corn and scallions. Stir in cilantro, lime juice, and 1/2 teaspoon of the salt.
Cut avocado in half; scoop avocado pulp into a bowl. Add remaining 1/4 teaspoon salt, and mash with a fork until mostly smooth.
Grill scallops in a hot grill pan until grill marks appear, 1 1/2 to 2 minutes on each side. Remove from heat.
Spread each warm corn tortilla with avocado mixture; top with 4 or 5 grilled scallops and a spoonful of corn pico. Serve with lime wedges.