Remove the jalapeños and vegetables (typically carrots and onions) that have been packed with them; reserve the liquid. Cut the stems off 2 to 3 of the jalapeños, cut them in half and scrape the seeds out; discard stems and seeds. Thinly slice the chiles (you need about 1/4 cup). Thinly slice some of the vegetables (you need about 1/4 cup of these also).
In a large skillet, heat the olive oil over medium. When hot, add the onion and cook until richly golden, about 10 minutes. Remove from the heat and stir in 1/4 cup of the jalapeños pickling juice. Let cool. Stir the onions into the tuna, along with the sliced jalapeños and vegetables and the parsley or herbs. Set out for your guests to roll into warm tortillas to make soft tacos.
This recipe is -awesome-! It’s a sleeper hit. I didn’t expect the combination of ingredients to be so amazing, but they are. Pickled jalapenos are very mild. But the chiles could be omitted for diners sensitive to spice
We love this recipe, but had been making it from Food & Wine’s Best of the Best Vol. 14, which calls for 1/4 c. olive oil. It makes sense to use less, although I see you call for oil-packed tuna here. I think it’s easier to read the recipe if you start with cooking the onions, then proceed with jalapenos, etc. My husband has made your chipotle-glazed baby back ribs twice to rave reviews! We hope to someday visit your restaurants in Chicago.