Halve the pepper, remove the stems, pith, and seeds, then cut into thick strips. Put the pepper strips and 1 teaspoon of olive oil in a bowl and toss to coat. Heat a large skillet over medium-high heat; once the skillet is hot, add the peppers and char them for 2 to 3 minutes on each side. Transfer to a cutting board or plate to cool.
In the bowl, toss the green onions with 1 teaspoon olive oil. Add them to the skillet (in two batches if necessary) and char them for 2 to 3 minutes on each side, then transfer to the cutting board. Once cool, cut into 1-inch chunks. Return the green onions and pepper to the bowl. Sprinkle with salt and pepper.
In another bowl, toss the corn with a teaspoon of olive oil. Add to the hot skillet and cook, stirring occasionally, until softened and lightly charred, 4 to 6 minutes. Remove the skillet from the heat and stir in the butter. Return the corn to its bowl and stir in the beans.
In a small bowl, combine the sour cream, juice of 1 lime, hot sauce, a pinch of salt, and a tablespoon of water; mix well. Add to the bowl with the corn and beans, and mix well. Season to taste with salt and pepper.
In another small bowl, combine the chile powder, cumin, and a pinch of salt.
Arrange a third of the pepper-onion mixture and a third of the corn-bean mixture on a platter or in a serving bowl. Sprinkle with some of the feta, some of the chile mixture, and some cilantro. Repeat the layers until all the ingredients are used. Add a squeeze of lime before serving.