Heat a large skillet over medium heat. Add the diced onion and bell pepper and cook for about 8 minutes stirring occasionally until the vegetables are tender and lightly golden. If they start to stick, add a small splash of water or broth. 

Add the frozen chopped spinach directly to the pan. Cook, stirring frequently, until thawed and most of the moisture has cooked off, about 8–10 minutes.

Stir in the corn and black beans.

Add the chili powder, cumin, salt, garlic, sugar, paprika, and dill. Stir well until everything is evenly combined, then remove from heat.

Lay out an egg roll wrapper on a clean surface with one corner pointing toward you. Scoop about 2 tablespoons of filling into the center.

Lightly dampen the edges of the wrapper with water. Fold the bottom corner up over the filling, fold the sides inward, then roll tightly into a cylinder. Press gently to seal and set seam-side down. Repeat with remaining wrappers.

Heat a nonstick skillet or griddle over medium heat and lightly coat with oil (I used an avocado oil spray).

Place a few egg rolls seam-side down in the pan, leaving space between them. Cook in batches, about 1½–2 minutes per side, turning carefully until golden and crispy on all sides.

Transfer cooked egg rolls to a cooling rack to prevent sogginess. Repeat with remaining egg rolls, adding more oil as needed.

Serve warm, sliced in half on the diagonal if desired, with ranch for dipping.