Place a large cast-iron skillet over medium heat. Once skillet is warm, add oil, then dulse and liquid smoke. Toss to combine. Cook, stirring often, until dulse is crispy, about 5 minutes. Remove dulse from heat and season with pepper.
Mash avocados with cilantro, scallions, and lime juice. Season with salt and pepper.
Slice pitas in half and toast lightly. Gently open them and divide avocado mixture evenly among all 8 halves. Divide greens, tomatoes, and dulse evenly among pitas and serve.
Recipes from The No Meat Athlete Cookbook: Whole Food, Plant-Based Recipes to Fuel Your Workouts and the Rest of Your Life. Copyright © 2017 Matt Frazier and Stepfanie Romine. Reprinted by permission of The Experiment.