For the bulgur: Bring 1/3 cup water to a boil in a small saucepan; add the bulgur, season with salt and simmer over low heat, covered, until tender, 10 minutes. Add the olive oil and fluff with a fork; let cool.
For the grilled vegetables: Slice the eggplant and zucchini lengthwise 1/2 inch thick. Toss with olive oil and salt in a large bowl. Cook on a grill pan over medium-high heat, turning, until tender, about 8 minutes. Let cool, then coarsely chop.
For the tomatoes: Toss together the tomatoes, mint, parsley, onion, olive oil and lemon juice in a medium bowl.
For the tzatziki: Combine the yogurt, cucumber, lemon juice and olive oil in a small bowl. Season with salt and pepper to taste.
Spread the hummus in the bottom of a 2-quart bowl or small trifle dish. Top with the chopped olives. Add the chopped grilled vegetables, then the tzatziki. Top with the cooked bulgur, then the tomato mixture. Crumble the feta in an even layer over the top. Scoop out the dip with a big spoon and serve with the pita chips.
Courtesy of Food Network Magazine, Photograph by Charles Masters