Note this is for summer growing, not spring (to encourage root growth) or fall because frost is coming.

This is strictly to get fewer but larger peppers.

Are your current fruits not growing to their full size?

I think they are ok but if I could get bigger, but fewer fruits I would do it. I trim other plants and never really thought about peppers just seeing what others do.

No, I want as much foliage as I can get to shade the fruit from sunscald.

If your fruits are already growing to their full size and you aren't happy with that, then try growing a variety that has larger fruits. If they aren't growing to their full size, adjust their feed, water, or environment. Pruining isn't going to lead to larger fruit with peppers, any more than pruning a salad tomato plant makes the plant grow beefsteak sized tomatoes.

I'm trying a little different approach this year than I usually do. I pinched the tops of each stem when I planted them to make them bushier. Then I started harvesting immature peppers to try to trigger more production. I'm also using a new product - Castine Blend from Coast of Maine as an addition on the ground around the plant. So far it's going pretty well. I don't normally harvest peppers this early. And I will want some ripe red peppers at some point. But that's not what you are asking - making peppers grow larger....I'm not experienced enough to answer.

If you mean like the idea of pruning tomato "suckers" to force larger fruits, except with peppers? I don't think so, I think large pepper plants are good. You could try limiting the number of peppers on a plant by picking some small peppers, to try for quality peppers over quantity. I think it is a good idea to pick many "green peppers" because the plant keeps producing and thick-walled peppers may not ripen to red (orange, yellow) very well in the heat and humidity. Bell peppers tend to rot when turning red where I live.

I really don't see a problem with smaller size peppers until late Summer. You should be getting full size now.