This is a great, hearty salad with protein from chickpeas, plus green leaves, peppery radishes, and lots of umami flavor from the dressing.
Per serving:
Make the dressing: Whisk all vinaigrette ingredients together in medium bowl or jar until combined. Set aside.
Make the salad: Brush cut sides of romaine/cos lettuce halves with oil and sprinkle with salt. Heat cast-iron frying pan over medium-high heat. Once pan is hot, place lettuce halves oiled-side down in pan. Use spatula to press lettuce wedges into hot pan; they should sizzle. Continue to cook for 3 to 4 minutes, until lettuce is charred and lightly wilted but still vibrantly green in parts. Remove from pan and set aside.
Add a little more avocado or olive oil to pan, keeping heat at medium-high. Add chickpeas with cayenne pepper and pinch of salt. Cook for about 3 to 5 minutes, stirring occasionally, until chickpeas are heated through and golden in spots.
Serve romaine/cos lettuce, grilled-side up, scattered with chickpeas and sliced radishes. Drizzle dressing on top.