Stir together the mayonnaise, Sriracha, salt, onion powder, and garlic powder until smooth. Set aside.
Trim and wash the fresh green beans, then dry them thoroughly.
In a large bowl, whisk together the flour, cayenne, cumin, black pepper, salt, garlic powder, and onion powder.
Pour in the beer and whisk until evenly combined.
Dip small batches of green beans into the batter and coat completely.
Heat vegetable oil in a large skillet suitable for frying.
Carefully add the battered green beans in small batches.
Fry until the coating is crisp and golden, turning as needed.
Remove with tongs or a slotted utensil and drain on a wire rack or paper towel-lined plate.
Repeat with the remaining green beans.
Serve immediately with Sriracha mayo.