Preheat the oven to 450°F with the rack in the middle. Rinse the peppers and pat them completely dry.
Place the peppers in a mixing bowl. Drizzle with avocado oil and toss until evenly coated. Sprinkle with kosher salt and toss again.
Spread the peppers on the sheet pan in a single layer, leaving space between them. Bake 8 to 10 minutes, flipping once halfway through. Start checking at 7 minutes.
Move the peppers to a plate as soon as they come out. Sprinkle with a little more salt and serve hot with the dipping sauce(quick recipe in the notes section).
Notes
For the shishito pepper sauce: In a small bowl, whisk together ½ cup mayonnaise, 1 tablespoon Sriracha, ½ teaspoon garlic powder, 1 minced garlic clove, and ¼ teaspoon red pepper flakes until smooth.
Use grapeseed or vegetable oil instead of avocado oil. Padron peppers also work well in this recipe.
Adjust the heat with your dipping sauce: use lemon juice for mild, shishito dipping sauce for medium, or red pepper flakes and hot sauce for more heat.
Roast on a bare metal sheet pan for better blistering and charring. Avoid parchment paper.
Store leftovers in the refrigerator for up to 3 days. They will soften, but you can reheat them in a hot dry skillet for 1–2 minutes.