Wash and dry produce.

In a small microwave-safe bowl, combine jalapeño, vinegar, ½ tsp sugar (1 tsp for 4 servings), salt, and pepper.

Cover with plastic wrap and microwave until jalapeño is softened, 30 seconds.

Keep covered, stirring occasionally, until ready to use in Step 5.

Heat a drizzle of oil in a large pan over high heat. Add corn; season with a pinch of sugar, salt, and pepper. Cook, stirring occasionally, until golden brown and lightly charred in spots, 4-6 minutes. (Cover pan with a lid if corn starts to pop!)

Turn off heat; transfer corn to a large bowl. Wipe out pan.

Heat a large drizzle of oil in same pan over medium-high heat. Working in batches, add tortillas and cook until crisped and golden, 1-3 minutes per side. TIP: Add more oil in between batches if pan looks dry; lower heat if browning too quickly.

Transfer tortillas to a paper-towel-lined plate until ready to assemble tostadas in Step 6.

To bowl with charred corn, add tuna, tomato, shallot, half the cilantro, half the mayonnaise, a drizzle of olive oil, salt, pepper, and as much chili powder as you like. Stir until thoroughly combined.

Drain jalapeño, reserving pickling liquid.

In a second small bowl, stir together sour cream, lime zest, drained jalapeño, remaining mayonnaise, and splashes of pickling liquid until smooth. Season with salt and pepper.

Divide tortillas between plates and top with tuna salad. Drizzle with jalapeño crema and sprinkle with remaining cilantro. Serve with lime wedges on the side.