Preheat oven to 400 degrees. Cover a baking sheet with foil and spray with nonstick cooking spray.
In a medium bowl, smash the sardines with a folk until it's flaked like tuna in a can.
Add egg, dill, lime juice, sesame seeds, sriracha, and brown rice. Season with salt and pepper. Mix well.
Pour panko onto a plate.
Grab 1/5 of the mixture (a small handful) and form into a patty. Note: it will be fairly damp. Don't squeeze too hard.
Continue to form patty in the panko until it is covered. Place on baking sheet.
Repeat for all 5 fritters. Spray tops of fritters with nonstick cooking spray.
Bake for 11 minutes. Remove from oven. Flip the fritters and cook for another 11 minutes. Note: you may want to broil for a minute or two for crispy brown tops.
Serve with additional Srirachi and lime wedges.