Dissolve the honey in 1-1/2 cups luke-warm water. Using a stand mixer fitted with the dough hook, mix the flour, 1-1/2 tsp. of the salt, and the yeast on low speed for 2 minutes. With the mixer running, gradually add the honey water and the olive oil. Increase the speed to medium and mix until the dough pulls away from the sides of the bowl and is smooth yet slightly tacky to the touch, about 5 minutes. If the dough seems too wet, add more flour, 1 tsp. at a time. Return to low speed and mix for 2 minutes more.
Let the dough rest in the bowl for 5 minutes and then turn the mixer to medium-high speed and mix for 3 minutes more, as the dough vigorously slaps against the side of the bowl.
Lightly oil a large bowl. Transfer the dough to the bowl and turn the dough to coat it with the oil. Cover with a damp cloth or plastic wrap and let the dough rise in a warm place until doubled in size, 1 to 1-1/2 hours.
Using a mortar and pestle, coarsely grind the cumin, coriander, and the remaining 3/4 tsp. salt. Set aside.
Cut the onion in half crosswise. Heat a cast-iron griddle or a small cast-iron skillet over high heat until very hot. Put the onion halves cut side down on the hot surface and cook until just charred, 5 to 7 minutes. Cool slightly and then remove the skin and chop finely. Put the onion in a medium bowl and stir in the chickpeas and about two-thirds of the spice mixture. With lightly floured hands gently deflate the dough. Add the chickpea mixture to the top of the dough, and using a plastic bowl scraper, reach down to the bottom of the bowl and gently fold the dough onto itself 4 times, rotating the bowl with each fold, to incorporate the mixture. Turn the dough out onto a lightly floured surface, stretch slightly to form into a log, and cut into 6 equal pieces. Shape each piece into a ball by gently stretching and tucking the dough underneath itself to form a “belly button” on the bottom. Gently roll in the palm of your hand to reshape into a uniform ball, then set each ball, belly button side down, on a well-floured baking sheet. Lightly brush each top with olive oil. Cover loosely with a towel or plastic wrap and let rise until doubled in size, about 1 hour.
Meanwhile, prepare a medium gas grill fire or an indirect charcoal fire with a hot zone and a cool zone (an oven thermometer placed over the hot zone should register about 450°F). Brush the grill grates with a stiff brush, then wipe with a lightly oiled paper towel.
On a lightly floured surface, roll out or press and stretch each piece of dough with your fingertips until about 1/4 inch thick and about 8 inches in diameter. Put the flatbreads on 2 lightly floured baking sheets and lightly brush the tops of the dough with the butter, being careful not to get butter on the baking sheet.
Put the flatbreads buttered side down on the grill (over the hot zone of the charcoal fire), cover, and cook until puffed and good grill marks form, 2 to 4 minutes. Flip the flatbreads and turn the burners of a gas grill down to low (or move the breads to the cool zone of the charcoal grill), and brush the grill-marked side with more butter. Cover and finish cooking until the bottoms have good grill marks and the breads are cooked through, about 3 minutes more. Transfer the breads to a cutting board, brush with more of the butter, and dust with the remaining spice mixture. Cut into wedges and serve warm.
The dough for both the Grilled Chickpea Flatbread and the Grilled Olive-Orange-Fennel Flatbread can be prepared ahead and refrigerated or frozen. After the dough has been shaped into uniform balls, put them in separate oiled zip-top plastic bags and refrigerate for up to 2 days or freeze for up to 1 month. Thaw frozen dough overnight in the refrigerator. Allow thawed or refrigerated dough to come to room temperature and double in size, about 1-1/2 hours, before continuing as directed in the recipes.