Final answer:
Without a recipe or ratio, it's impossible to determine how many teaspoons of toasted sesame seeds are equivalent to 2/3 teaspoon of pepper flakes as there is no standard conversion for these ingredients.
Step-by-step explanation:
The question asks us to determine how many teaspoons of toasted sesame seeds are equivalent to 2/3 teaspoon of pepper flakes. Without additional information such as a recipe ratio, this question cannot be accurately answered as the conversion between sesame seeds and pepper flakes is not standardized. Typically, the amount of each ingredient would be based on a recipe or personal taste preference. To provide an accurate answer, further context like the specific recipe ratio is necessary.