Preheat the oven to 425°F (220°C) and line a baking sheet.
Heat a large skillet over medium-high heat and cook the ground chicken, breaking it up, until mostly cooked, about 4–5 minutes.
Add the chopped onion and chopped poblano or bell pepper to the skillet and cook until softened and the chicken is fully cooked, about 4–5 minutes more.
Stir in the chopped garlic, dried oregano, ground cumin, cayenne, salt, black pepper, and 1/2 cup water; cook until fragrant and most liquid has reduced, about 5 minutes.
Mix in the chopped pepperoncini, remove the skillet from the heat, and let the filling cool slightly.
Warm the corn tortillas in the microwave in 30-second intervals or on a hot comal until pliable. Keep them covered so they stay soft.
Lightly coat one side of each warmed tortilla with olive oil. Place about 2 tablespoons of the chicken mixture down the center of each tortilla and roll tightly, placing seam-side down on the prepared baking sheet.
Bake the taquitos for 10 minutes, until the tortillas begin to crisp.
Pour the red enchilada sauce evenly over the baked taquitos and sprinkle with shredded Swiss and pepper jack cheeses.
Return to the oven and bake until the cheese is melted and bubbling, about 10 minutes more.
While the taquitos bake, make the pineapple-jalapeño salsa by combining diced pineapple, chopped jalapeño, chopped cilantro, and lime juice in a bowl; season with sea salt to taste.
Serve the taquitos topped with chopped or sliced avocado, a dollop of Greek yogurt, and the pineapple-jalapeño salsa.