In a small bowl stir together peanut butter, sour cream, 1 tablespoon lime juice, and 2 teaspoons soy sauce until combined. In a large bowl blend together ground chuck, remaining 2 teaspoons soy sauce, remaining tablespoon lime juice, coriander, gingerroot, red pepper flakes, and salt and pepper to taste until just combined. Form mixture into four 1-inch-thick patties. When forming patties, handle meat as little as possible for a juicier burger.