Those sound like the kind of temperatures we get here in North Texas (today will probably hit 40C - we have a hot week forecast!). Every summer for the last 10 years I've grown peppers in those conditions. Peppers are adapted to heat stress, so they'll appear to wilt during the day (leaves turn floppy like thin paper) but will perk up with a good watering. So give them a good watering each evening.
Also, peppers usually stop producing fruit during those conditions. There will be flowers, but no fruit. We get fruit in late spring/early summer (May to June) and then the main crop September-November. By watering the peppers during the summer, the plants grow good stems and leaves - ready for fruit production in the cooler months.
I have had some exceptions in recent years. Last year "Gypsy" (smaller, yellow bell pepper) was very prolific with lots of fruit throughout summer. Also this year, I'm still getting fruit on my peppers (new house, and the bed is probably particularly good nutritionally) - varieties are: Cayenne, Pimento, Big Jim (Anaheim), and Sweet Banana.
re. @Rory's suggestions: There are cacti for all temperatures (some grow in the wild in Canada) - the main requirement is good well draining soil. Prickly pears are particularly easy to grow and cuttings are very easy. We have some zinnia I sowed back in March and we now have flowers, and they don't appear to be wilting.
Do you have water and humidity? If so, consider tropical plants. We have bananas with fruit on them - in North Texas! (the books describe it as rare for south Texas and don't even both with the possibility up here due to our frosts). In a tropical environment, bananas will provide some shade and bring in lots of animals and birds.