Cut the sausage into ½" rounds.
Heat a 12" cast-iron skillet over high heat until it is smoking.
In a medium bowl, combine the shishito peppers with 2 teaspoons of the canola oil until they are well coated.
Cook the shishito peppers in the cast-iron skillet for 3 to 5 minutes, stirring frequently until they blister in places.
Place the peppers back in the bowl and season well with kosher salt.
Reduce the heat to medium-high and add 2 more teaspoons of oil to the skillet, then add the sausage rounds.
Cook the sausage for a few minutes on each side until cooked through.
Add the peppers back to the skillet to warm through.
To make the sauce; combine the sriracha with the mayonnaise in a small bowl. Add more sriracha if you prefer it spicier.
Serve the peppers and sausage over rice and drizzle the sauce on top.
