Wash the chicken and pat dry, then slice each breast into long strips about 1 inch wide.
In a medium bowl whisk together the beaten eggs, soy sauce, yellow mustard, all-purpose flour, cornstarch, chopped dill, and salt and pepper until smooth to form the batter.
Place the sesame seeds in a shallow bowl or plate for dredging.
Heat the vegetable oil in a nonstick skillet over medium heat until shimmering but not smoking.
Dip each chicken strip into the batter to coat completely, then press or roll the strip in the sesame seeds to cover evenly.
Fry the coated chicken strips in the hot oil, working in batches if needed, about 3–5 minutes per side until golden brown and cooked through (internal temperature 165°F/74°C), adjusting heat to maintain medium.
Transfer cooked strips to a paper towel–lined plate to drain, then repeat with remaining chicken.
Serve the sesame crusted chicken hot with sweet chili sauce on the side if desired.
