Here is a list of the top ten smallest fast foods based on their size:

1. Mini Burgers/Sliders:

These tiny burgers are typically about 2-3 inches in diameter, making them one of the smallest fast food options.

2. Chicken Nuggets:

Chicken nuggets are small breaded and fried pieces of chicken, usually measuring about 1-2 inches in size.

3. Mini Tacos:

Miniature versions of tacos are often served as appetizers or snacks, and they are typically about 3-4 inches in length.

4. Mini Hot Dogs:

Similar to sliders, mini hot dogs are bite-sized versions of the classic hot dog, usually measuring around 2-3 inches in length.

5. Chicken Wings:

Chicken wings are a popular finger food, and while they vary in size, the smaller wingettes or drumettes can be quite small, measuring about 2-3 inches in length.

6. Mini Pizza Bagels:

These bite-sized snacks consist of mini bagels topped with pizza sauce, cheese, and various toppings. They are usually around 2-3 inches in diameter.

7. Miniature Empanadas:

Empanadas are small turnovers filled with various ingredients. The mini versions are typically about 2-3 inches in diameter.

8. Mini Doughnuts:

Miniature doughnuts are small, bite-sized treats that are typically about 1-2 inches in diameter.

9. Mini Spring Rolls:

Spring rolls are a popular appetizer in many cuisines. Mini spring rolls are about 2-3 inches long and are often served as finger foods.

10. Mini Quesadillas:

These small tortilla-based snacks are usually filled with cheese and other ingredients. They are typically about 3-4 inches in diameter.

Please note that serving sizes and dimensions may vary depending on the restaurant or region.