Smoky Chicken Tostadas

Name: Smoky Chicken Tostadas
Ingredients: 3 jalapeños, 1 thinly sliced and 2 seeded and finely chopped, divided; 3 tbsp. fresh lime juice, divided; None Kosher salt and pepper; 0.25 tsp. plus a pinch of sugar; 1 tbsp. olive oil; 1 small Vidalia onion (about 4 ounces), chopped; 2 cloves garlic, finely chopped; 2 tbsp. tomato paste; 2 tsp. chili powder; 1 tsp. ground cumin; 1 tsp. dried oregano; 1 8-ounce can tomato sauce; 3 c. shredded rotisserie chicken; 2 avocados, diced; 8 corn tostadas, warmed; 0.5 c. crumbled cotija cheese