Step 1

Preheat oven to 325°. Toast seeds on a parchment paper–lined rimmed baking sheet, tossing once, until darkened and fragrant, 8–10 minutes. Transfer to a small bowl; reserve baking sheet and parchment.

Step 2

Meanwhile, combine flour and 2 tsp. Diamond Crystal or 1 tsp. Morton salt in a large bowl. Add 2 tsp. oil and 1 cup warm water and mix with a sturdy spatula or your hands to combine. If dough feels dry, add more water 1 tablespoonful at a time until it holds together. Smash and knead dough until smooth and no small clumps or dry bits remain (be patient and really knead it—it will hydrate and come together); it shouldn’t crack when you squeeze it. Cover bowl with a damp kitchen towel and set aside to let dough hydrate, 15 minutes.

Step 3

Halve chile lengthwise, removing seeds and membranes if less heat is desired. Place one half in a food processor. Finely chop remaining chile and set aside. Add avocado, ½ cup cilantro, and juice from 1 lime to food processor and pulse until mostly smooth. With the motor running, drizzle in 2 Tbsp. oil until a smooth sauce forms. Taste and season with salt.

Step 4

Add all but 2 Tbsp. toasted seeds to hydrated dough. Knead in bowl until seeds are incorporated and dough is firm and homogenous, 1–2 minutes. Turn out dough onto reserved parchment and divide into 4 pieces. Press and pat into disks that are 5"–5½" in diameter and ⅛"–¼" thick. Return disks with parchment to baking sheet.

Step 5

Heat 1 tsp. oil in a large cast-iron or nonstick skillet over medium-high until shimmering. Working in batches, add arepas and cook, turning once with a spatula and reducing heat to medium if they’re browning too quickly, until a crisp, slightly charred crust forms, 3–5 minutes per side. Transfer arepas to same baking sheet and bake until slightly puffed and springy, 10–12 minutes.

Step 6

While arepas bake, wipe out skillet, then pour in remaining 1 Tbsp. oil and heat over medium. Add chili powder and cook, stirring, until fragrant, about 20 seconds. Add beans and cook, stirring frequently, until warmed through, 3–4 minutes. Add reserved chopped chile and cook, stirring, until fragrant, about 1 more minute. Remove from heat and add remaining ½ cup cilantro. Season with salt.

Step 7

Spread arepas with avocado sauce. Top with bean mixture, cheese (if using), and reserved seeds.