To prepare stuffed jalapeños, place peppers on a foil-lined baking sheet; broil 12 minutes or until blackened, turning occasionally. Place in a zip-top plastic bag; seal. Let stand 15 minutes; peel jalapeños. Cut a lengthwise slit in each, discarding stems, seeds, and membranes.
Place a medium nonstick skillet coated with cooking spray over low heat until hot. Add bell pepper, onion, and garlic, and cook 5 minutes or until soft. Remove from heat; stir in crabmeat, 1 tablespoon cilantro, and 1/4 teaspoon salt. Divide crab mixture evenly among jalapeños (each will be very full).
Preheat oven to 375°.
Beat the egg whites in a medium bowl at high speed of a mixer until soft peaks form. Fold in yogurt.
Combine breadcrumbs, cornmeal, 1 teaspoon salt, and garlic powder in a small bowl. Dip each stuffed jalapeño in the egg white mixture; dredge in the breadcrumb mixture. Place the breaded jalapeños on a baking sheet coated with cooking spray. Lightly spray jalapeños with cooking spray. Bake at 375° for 15 minutes or until golden.
To prepare avocado dunk, place avocado and remaining ingredients in a food processor or blender, and process until smooth.