How to Make It
Place onion wedges in a small bowl. Whisk together vinegar, sugar, 1/2 cup water, and 1 tablespoon of the salt in a bowl until sugar and salt dissolve. Pour mixture over onion wedges; let stand 1 hour.
Pulse salmon cubes in a food processor until coarsely chopped, 5 to 8 times. (Do not overpulse.) Stir together panko, mayonnaise, mustard, jalapeño, 1/4 cup of the cilantro, and 1/2 teaspoon each of the salt and black pepper in a medium bowl. Add salmon to mixture; toss to combine. Form salmon mixture into 4 (1/2-inch-thick) patties. Transfer to a plate lined with parchment paper; cover with plastic wrap. Refrigerate at least 30 minutes or up to overnight.
Meanwhile, using tongs, cook poblano directly over flame of a gas stovetop burner on medium-high heat, turning occasionally, until lightly charred on all sides, 6 to 8 minutes. Transfer to a bowl; cover tightly with plastic wrap. Let stand 15 minutes. Remove and discard peel, stem, seeds, and core from poblano. Transfer poblano flesh to a blender. Add sour cream, garlic, 1 tablespoon of the lime juice, 1 tablespoon water, and remaining 1/4 teaspoon salt, 1/4 cup cilantro, and 1/2 teaspoon black pepper; blend until smooth, about 30 seconds, stopping to scrape down sides as needed. Refrigerate until serving.
Preheat a gas or charcoal grill to high (450°F to 500°F), and grease grates with canola oil. Place salmon patties on grates; grill until grill marks form and a thermometer inserted in thickest portion of patties registers 145°F (for medium-well), 4 to 5 minutes per side. Remove from grill.
Toss together arugula, radishes, olive oil, and remaining 1 tablespoon lime juice in a bowl. Divide mixture evenly among 4 plates; top with marinated onion wedges (discard the liquid), patties, and poblano cream.
Also appeared in: Health, July, 2019