Clean and cut the bell peppers into fourths, removing the seeds. Place peppers on a grill over high heat, skin side down, making sure not to put them too close together. Grill the peppers until skins are very charred, about 20-25 minutes, depending on your grill. Place peppers in a bowl and cover with plastic wrap. Let steam for about 15 minutes. Then peel off skins and discard, and cut peppers into short thick strips.
Place olives into a colander and let them drain. Spoon out 2 T capers into a small strainer; then rinse the capers and let them drain. Wash marjoram (or other herb of your choice), dry, and chop.
Whisk together the olive oil, vinegar, caper brine, minced garlic, salt, and pepper to make the dressing. Combine grilled pepper strips, olives, capers, tomatoes, cucumbers and dressing in a large bowl.
This salad can be served right away or allowed to marinate for several hours at room temperature until you're ready to serve it.