Scallop Ceviche with Aguachile

Name: Scallop Ceviche with Aguachile
Ingredients: 1 pound sea scallops, sliced crosswise 1/4 inch thick; 3/4 cup fresh lime juice; 1 jalapeño—stemmed and chopped, half the seeds discarded; 4 ounces English cucumber, seeded and coarsely chopped, plus 1/2 cup thinly sliced cucumber; 1 small garlic clove, smashed; 1/4 cup lightly packed cilantro; 1/4 cup lightly packed parsley; 1 tablespoon mint; 1/2 tablespoon canola oil; 2 tablespoons water; Kosher salt; 3/4 cup thinly sliced red onion; Tostadas or tortilla chips, for serving