Freekeh (pronounced FREAK-eh), a type of young, green wheat, contains super-filling resistant starch.
Cook freekeh according to package directions. Heat a large skillet over medium-high heat. Add oil to pan; swirl to coat. Add onion and garlic; sauté for 5 minutes. Add turkey; sprinkle with chilli powder, sugar and red pepper. Cook, stirring to crumble, until turkey is done, about 6 minutes. Add cooked freekeh and tomatoes; reduce heat to medium and cook until mixture thickens, about 10 minutes. Stir in salt. Remove from heat; let stand for 5 minutes. Place 1 lettuce leaf on bottom half of each bun, if desired. Spoon about 2/3 cup freekeh mixture over lettuce. Top each sandwich with 1 onion slice and top half of bun.