How to Make It
Whisk together miso, soy sauce, vinegar, sesame oil, lime zest and juice, brown sugar, ginger, and jalapeño, if using, in a small bowl until miso is dissolved. Whisk in canola oil in a slow, steady stream until well combined. Set aside, or cover and refrigerate up to 1 week.
Preheat a grill to high (450°F to 500°F), or heat a grill pan over high. Brush corn and scallions with 1 tablespoon canola oil, and place on grates (or grill pan). Grill, uncovered, turning occasionally, until just tender and slightly charred, about 4 minutes for scallions and 10 minutes for corn. Remove from heat. When cool enough to handle, cut corn kernels off cobs, and roughly chop scallions into 1/2-inch pieces; set corn and scallions aside.
Remove and discard the small side muscle from each scallop; rinse under cold running water, and pat dry. Thread 3 scallops on 2 parallel skewers, and repeat with remaining 9 scallops on 6 skewers. Brush scallops with remaining 1 tablespoon canola oil, and season both sides with salt. Grill scallops, uncovered, until grill marks appear, about 1 minute and 30 seconds. Turn scallops, and grill until desired degree of doneness, about 30 seconds for medium (warm translucent center). Remove from grill, and set aside.
Toss together corn, scallions, edamame, and tomatoes in a large bowl. Add herbs, miso vinaigrette, and 1 teaspoon sesame seeds; toss to combine. Divide salad among 4 shallow bowls. Top each with a skewer of scallops. Sprinkle with remaining 1 teaspoon sesame seeds and additional herbs.